Light-emitting device and method for manufacturing the same

ABSTRACT

A highly reliable light-emitting device and a manufacturing method thereof are provided. A light-emitting element and a terminal electrode are formed over an element formation substrate; a first substrate having an opening is formed over the light-emitting element and the terminal electrode with a bonding layer provided therebetween; an embedded layer is formed in the opening; a transfer substrate is formed over the first substrate and the embedded layer; the element formation substrate is separated; a second substrate is formed under the light-emitting element and the terminal electrode; and the transfer substrate and the embedded layer are removed. In addition, an anisotropic conductive connection layer is formed in the opening, and an electrode is formed over the anisotropic conductive connection layer. The terminal electrode and the electrode are electrically connected to each other through the anisotropic conductive connection layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting device. The presentinvention also relates to a method for manufacturing the light-emittingdevice.

In this specification, a semiconductor device means all types of devicesthat can function by utilizing semiconductor characteristics, and anelectro-optical device, a light-emitting device, a display device, asemiconductor circuit, and an electronic appliance are all semiconductordevices.

2. Description of the Related Art

In recent years, research and development have been extensivelyconducted on light-emitting elements utilizing electroluminescence (EL).In a basic structure of such a light-emitting element, a layercontaining a light-emitting substance is interposed between a pair ofelectrodes. By applying voltage to the element, light emission from thelight-emitting substance can be obtained.

The above light-emitting element is a self-luminous element; thus, alight-emitting device including the light-emitting element hasadvantages such as high visibility, no necessity of a backlight, and lowpower consumption. In addition, the light-emitting device has advantagesin that it can be manufactured to be thin and lightweight and has fastresponse speed.

Since a light-emitting device including the above light-emitting elementcan be flexible, use of the light-emitting device for a flexiblesubstrate has been proposed.

As a method for manufacturing a light-emitting device using a flexiblesubstrate, a technique has been developed in which a semiconductorelement such as a thin film transistor is manufactured over a substratesuch as a glass substrate or a quartz substrate, for example, a spacebetween the semiconductor element and another substrate is filled withan organic resin, and then the semiconductor element is transferred fromthe glass substrate or the quartz substrate to the other substrate(e.g., a flexible substrate) (Patent Document 1).

In some cases, over a light-emitting element that has been formed over aflexible substrate, another flexible substrate is provided in order toprotect a surface of the light-emitting element or prevent entry ofmoisture or impurities from the outside.

Patent Document 2 and Patent Document 3 each disclose technologicalthought in which a groove is formed in a flexible substrate and part ofthe flexible substrate is removed along the groove in order to expose aterminal electrode to which an external signal is input.

PATENT DOCUMENT

Patent Document 1: Japanese Published Patent Application No. 2003-174153

Parent Document 2: Japanese Published Patent Application No. 2000-150143

Patent Document 3: Japanese Published Patent Application No. 2009-109770

SUMMARY OF THE INVENTION

In order to supply a signal or electric power to a light-emittingdevice, it is necessary that part of a flexible substrate be removed toexpose a terminal electrode so that an electrode such as a flexibleprinted circuit (FPC) is connected to the terminal electrode. Inaddition, it is preferable that the terminal electrode be provided neara display area in order to suppress signal attenuation, electric powerattenuation, or the like due to wiring resistance.

In the case where a flexible substrate is provided over a light-emittingelement or a terminal electrode, the flexible substrate is oftenprovided over the light-emitting element or the terminal electrode witha bonding layer provided therebetween. Thus, in the above-describedmethods disclosed in the patent documents, the bonding layer mightremain on the terminal electrode at the time of removal of a portion ofthe flexible substrate that overlaps the terminal electrode. Inaddition, the terminal electrode is damaged easily at the time ofremoval of the bonding layer.

A method in which part of a flexible substrate is removed by laser lightor with an edged tool has a problem in that a terminal electrodeincluded in a light-emitting device is damaged easily and thereliability and manufacturing yield of the light-emitting device arereduced easily. In addition, a display area and a terminal electrodeneed to be provided with a sufficient space therebetween in order toprevent damage to the display area due to the above-described method;for this reason, signal attenuation, electric power attenuation, or thelike due to an increase in wiring resistance is caused easily.

An object of one embodiment of the present invention is to provide amethod for manufacturing a light-emitting device that does not easilydamage a terminal electrode.

Another object of one embodiment of the present invention is to providea method for manufacturing a light-emitting device that does not easilydamage a display area.

Another object of one embodiment of the present invention is to providea highly reliable light-emitting device and a method for manufacturingthe same.

Another object of one embodiment of the present invention is to providea novel light-emitting device and a method for manufacturing the same.

One embodiment of the present invention is a method for manufacturing alight-emitting device that includes the steps of: forming alight-emitting element and a terminal electrode over an elementformation substrate with a separation layer provided therebetween;forming a first substrate having a first opening over the light-emittingelement and the terminal electrode with a bonding layer having a secondopening provided therebetween; forming an embedded layer in theopenings; forming a transfer substrate over the first substrate and theembedded layer; separating the element formation substrate from thelight-emitting element and the terminal electrode; forming a secondsubstrate below the light-emitting element and the terminal electrode;removing the transfer substrate and the embedded layer; forming ananisotropic conductive connection layer in the first opening and thesecond opening; and forming an external electrode electrically connectedto the terminal electrode through the anisotropic conductive connectionlayer.

In the method for manufacturing the light-emitting device, the firstopening of the first substrate and the second opening of the bondinglayer overlap the terminal electrode.

Using a flexible substrate as the first substrate enables a flexiblelight-emitting device to be manufactured. Using a flexible substrate asthe second substrate enables a flexible light-emitting device to bemanufactured.

It is preferable that the embedded layer be formed using a solubleresin.

Another embodiment of the present invention is a method formanufacturing a light-emitting device that includes the steps of:forming a light-emitting element and a terminal electrode over anelement formation substrate with a separation layer providedtherebetween; forming a first substrate over the light-emitting elementand the terminal electrode with a first bonding layer providedtherebetween; separating the element formation substrate from thelight-emitting element and the terminal electrode; forming a secondsubstrate having an opening under the light-emitting element with asecond bonding layer provided therebetween; forming an anisotropicconductive connection layer so as to overlap the opening; and forming anexternal electrode electrically connected to the terminal electrodethrough the anisotropic conductive connection layer.

Another embodiment of the present invention is a method formanufacturing a light-emitting device that includes: a first step offorming a separation layer over an element formation substrate; a secondstep of forming an insulating layer over the separation layer; a thirdstep of selectively removing part of the insulating layer to form afirst opening, in which part of the separation layer is exposed; afourth step of oxidizing an exposed surface of the separation layer; afifth step of forming a terminal electrode overlapping the firstopening; a sixth step of forming a light-emitting element; a seventhstep of forming a first substrate over the light-emitting element andthe terminal electrode with a first bonding layer provided therebetween;an eighth step of separating the element formation substrate; a ninthstep of forming a second substrate having a second opening under thelight-emitting element and the terminal electrode with a second bondinglayer provided therebetween; and a tenth step of forming an externalelectrode electrically connected to the terminal electrode in the secondopening. Note that overlap of the first opening with the second openingenables electrical connection between the terminal electrode and theexternal electrode.

Using a flexible substrate as the first substrate enables a flexiblelight-emitting device to be manufactured. Using a flexible substrate asthe second substrate enables a flexible light-emitting device to bemanufactured.

When attachment of the second substrate having the opening is performedso that the opening overlaps the terminal electrode, a region of thesecond substrate that overlaps the terminal electrode does not need tobe removed by laser light, with an edged tool, or the like; for thisreason, a display area and the terminal electrode are not easilydamaged. In addition, the distance between the display area and theopening can be shortened; thus, signal attenuation or electrical powerattenuation can be suppressed. In addition, the manufacturing process issimplified; thus, the productivity of the light-emitting device can beincreased.

One embodiment of the present invention is a light-emitting device thatincludes a light-emitting element and a terminal electrode over a firstsubstrate, a first layer over the terminal electrode, a second layerover the first layer, and a second substrate having a first portion overthe light-emitting element, the first layer, the second layer, and ametal layer with a bonding layer therebetween. The first portionoverlaps the terminal electrode, the first layer, and the second layer.

A flexible substrate is used as the first substrate. A flexiblesubstrate is used as the second substrate.

The first layer is formed using an organic material. The second layer isformed using a metal material.

Another embodiment of the present invention is a method formanufacturing a light-emitting device that includes the steps of:forming a light-emitting element and a terminal electrode over anelement formation substrate with a separation layer providedtherebetween; forming a first layer over the terminal electrode; forminga second layer over the first layer; forming a second substrate having afirst portion over the light-emitting element, the terminal electrode,the first layer, and the second layer with a bonding layer providedtherebetween so that the first portion overlaps the terminal electrode,the first layer, and the second layer; separating the element formationsubstrate from the light-emitting element and the terminal electrode;and forming a first substrate under the light-emitting element and theterminal electrode.

A flexible substrate is used as the first substrate. A flexiblesubstrate is used as the second substrate.

The first layer is formed using an organic material. The second layer isformed using a metal material.

Surrounding the first portion with perforations can facilitateseparation of the first portion from the second substrate. In addition,the first portion overlaps the first layer and the second layer, wherebythe bonding layer that the first portion overlaps can also be removed atthe time of the separation of the first portion and the terminalelectrode can be exposed easily.

The exposed terminal electrode can be electrically connected to anexternal electrode.

An FPC or a metal wire can be used as the external electrode. In thecase of using a metal wire as the external electrode, the metal wire andthe terminal electrode can be connected to each other by a wire bondingmethod or a soldering method without using an anisotropic conductiveconnection layer.

One embodiment of the present invention can provide a method formanufacturing a light-emitting device that does not easily damage aterminal electrode.

One embodiment of the present invention can provide a method formanufacturing a light-emitting device that does not easily damage adisplay area.

One embodiment of the present invention can provide a highly reliablelight-emitting device and a method for manufacturing the same.

One embodiment of the present invention can provide a novellight-emitting device and a method for manufacturing the same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view illustrating a light-emitting device and FIG. 1Bis a cross-sectional view illustrating the same.

FIGS. 2A to 2E are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 3A to 3C are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 4A and 4B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 5A and 5B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 6A and 6B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 7A to 7D are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 8A and 8B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 9A and 9B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIG. 10A is a top view illustrating a light-emitting device and FIG. 10Bis a cross-sectional view illustrating the same.

FIG. 11A is a perspective view illustrating a light-emitting device andFIG. 11B is a top view illustrating the same.

FIG. 12 is a cross-sectional view illustrating a light-emitting device.

FIGS. 13A to 13D are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 14A to 14D are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 15A to 15C are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIG. 16A is a perspective view illustrating a light-emitting device andFIG. 16B is a cross-sectional view illustrating the same.

FIG. 17A is a perspective view illustrating a light-emitting device andFIG. 17B is a cross-sectional view illustrating the same.

FIGS. 18A and 18B are perspective views illustrating a light-emittingdevice and FIGS. 18C and 18D are cross-sectional views illustrating thesame.

FIGS. 19A and 19B are perspective views illustrating a light-emittingdevice and FIG. 19C is a cross-sectional view illustrating the same.

FIG. 20A is a perspective view illustrating a light-emitting device andFIG. 20B is a cross-sectional view illustrating the same.

FIGS. 21A to 21E are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 22A and 22B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 23A and 23B are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 24A to 24C are cross-sectional views illustrating a method formanufacturing a light-emitting device.

FIGS. 25A to 25E illustrate arrangement examples of grooves.

FIGS. 26A to 26E illustrate arrangement examples of grooves.

FIG. 27A is a perspective view illustrating a light-emitting device andFIG. 27B is a cross-sectional view illustrating the same.

FIGS. 28A and 28B illustrate structure examples of light-emittingelements.

FIGS. 29A to 29E illustrate examples of electronic appliances andlighting devices.

FIGS. 30A and 30B illustrate an example of an electronic appliance.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments will be described in detail with reference to theaccompanying drawings. Note that the present invention is not limited tothe description below, and it is understood easily by those skilled inthe art that various changes and modifications can be made withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be construed as being limited to thedescription in the following embodiments. In the structures of thepresent invention to be described below, the same portions or portionshaving similar functions are denoted by the same reference numerals indifferent drawings, and explanation thereof will not be repeated.

Note that in each drawing referred to in this specification, the size ofeach component or the thickness of each layer might be exaggerated or aregion might be omitted for clarity of the invention. Therefore,embodiments of the invention are not limited to such scales. Especiallyin a top view, some components might not be illustrated for easyunderstanding.

The position, size, range, and the like of each component illustrated inthe drawings and the like are not accurately represented in some casesto facilitate understanding of the invention. Therefore, the disclosedinvention is not necessarily limited to the position, the size, range,and the like disclosed in the drawings and the like.

Note that ordinal numbers such as “first” and “second” in thisspecification and the like are used in order to avoid confusion amongcomponents and do not denote the priority or the order such as the orderof steps or the stacking order. A term without an ordinal number in thisspecification and the like might be provided with an ordinal number in aclaim in order to avoid confusion among components. In addition, a termwith an ordinal number in this specification and the like might beprovided with a different ordinal number in a claim. Moreover, anordinal number provided for a term in this specification and the likemight be omitted in a claim.

In addition, in this specification and the like, the term such as an“electrode” or a “wiring” does not limit a function of a component. Forexample, an “electrode” is used as part of a “wiring” in some cases, andvice versa. Further, the term “electrode” or “wiring” can also mean acombination of a plurality of “electrodes” and “wirings” formed in anintegrated manner.

Note that the term “over” or “under” in this specification and the likedoes not necessarily mean that a component is placed “directly on” or“directly below” and “directly in contact with” another component. Forexample, the expression “electrode B over insulating layer A” does notnecessarily mean that the electrode B is on and in direct contact withthe insulating layer A and can mean the case where another component isprovided between the insulating layer A and the electrode B.

Embodiment 1

A structure example of a light-emitting device 100 of one embodiment ofthe present invention is described with reference to FIGS. 1A and 1B.FIG. 1A is a top view of the light-emitting device 100 and FIG. 1B is across-sectional view taken along the dashed-dotted line A1-A2 in FIG.1A. Note that the light-emitting device 100 disclosed in thisspecification is a display device in which a light-emitting element isused as a display element.

<Structure of Light-Emitting Device>

The light-emitting device 100 described in this embodiment includes anelectrode 115, an EL layer 117, an electrode 118, a partition 114, and aterminal electrode 116. The electrode 115 and the terminal electrode 116are electrically connected to each other. In addition, in thelight-emitting device 100, the partition 114 is formed over theelectrode 115, the EL layer 117 is formed over the electrode 115 and thepartition 114, and the electrode 118 is formed over the EL layer 117.

A light-emitting element 125 includes the electrode 115, the EL layer117, and the electrode 118. In addition, the light-emitting element 125is formed over a substrate 111 with a bonding layer 112, a separationlayer 113, and a base layer 119 provided therebetween. Note that aplurality of light-emitting elements 125 are provided in a display area131.

In the light-emitting device 100 described in this embodiment, asubstrate 121 is formed over the electrode 118 with a bonding layer 120provided therebetween. The substrate 121 has an opening 122 aoverlapping the terminal electrode 116. The bonding layer 120 has anopening 122 b that the opening 122 a overlaps. In this specification,the opening 122 a and the opening 122 b are collectively called anopening 122. In the opening 122, an external electrode 124 and theterminal electrode 116 are electrically connected to each other throughan anisotropic conductive connection layer 123.

A switching element for controlling a signal supplied to thelight-emitting element 125 may be provided between the light-emittingelement 125 and the terminal electrode 116. For example, a transistormay be provided between the light-emitting element 125 and the terminalelectrode 116.

A transistor is a kind of semiconductor element and enablesamplification of current or voltage, switching operation for controllingconduction or non-conduction, or the like. By providing a transistorbetween the light-emitting element 125 and the terminal electrode 116,the area of the display area 131 can be increased easily and ahigher-resolution display can be achieved easily. Note that a resistor,an inductor, a capacitor, or the like, without limitation to a switchingelement such as a transistor, can be provided in the display area 131.

<Substrates>

An organic resin material, a glass material that is thin enough to haveflexibility, or the like can be used for the substrate 111 and thesubstrate 121. In the case where the light-emitting device 100 is abottom-emission light-emitting device or a dual-emission light-emittingdevice, a material that transmits light emitted from the EL layer 117 isused for the substrate 111. In the case where the light-emitting device100 is a top-emission light-emitting device or a dual-emissionlight-emitting device, a material that transmits light emitted from theEL layer 117 is used for the substrate 121.

As a material that has flexibility and transmits visible light, whichcan be used for the substrate 111 and the substrate 121, the followingcan be used: a polyethylene terephthalate resin, a polyethylenenaphthalate resin, a polyacrylonitrile resin, a polyimide resin, apolymethylmethacrylate resin, a polycarbonate resin, a polyethersulfoneresin, a polyamide resin, a cycloolefin resin, a polystyrene resin, apolyamide imide resin, a polyvinylchloride resin, or the like.

The thermal expansion coefficients of the substrate 111 and thesubstrate 121 are preferably less than or equal to 30 ppm/K, morepreferably less than or equal to 10 ppm/K. In addition, on surfaces ofthe substrate 111 and the substrate 121, a protective film having lowwater permeability may be formed in advance; examples of the protectivefilm include a film containing nitrogen and silicon such as a siliconnitride film or a silicon oxynitride film and a film containing nitrogenand aluminum such as an aluminum nitride film. Note that a structure inwhich a fibrous body is impregnated with an organic resin (also calledprepreg) may be used as the substrate 111 and the substrate 121.

<Base Layer>

The base layer 119 is preferably formed as a single layer or amultilayer using silicon oxide, silicon nitride, silicon oxynitride,silicon nitride oxide, aluminum oxide, aluminum oxynitride, aluminumnitride oxide, or the like. The base layer 119 can be formed by asputtering method, a CVD method, a thermal oxidation method, a coatingmethod, a printing method, or the like.

The base layer 119 can prevent or reduce diffusion of impurity elementsfrom the substrate 111, the bonding layer 112, or the like to thelight-emitting element 125.

<Terminal Electrode>

The terminal electrode 116 can be formed using a conductive material.For example, a metal element selected from aluminum, chromium, copper,silver, gold, platinum, tantalum, nickel, titanium, molybdenum,tungsten, hafnium (Hf), vanadium (V), niobium (Nb), manganese,magnesium, zirconium, beryllium, and the like; an alloy containing anyof the above metal elements; an alloy containing a combination of theabove metal elements; or the like can be used. A semiconductor typifiedby polycrystalline silicon including an impurity element such asphosphorus, or silicide such as nickel silicide may also be used. Thereis no particular limitation on the formation method of the conductivematerial, and a variety of formation methods such as an evaporationmethod, a CVD method, a sputtering method, and a spin coating method canbe employed.

The terminal electrode 116 can also be formed using a conductivematerial containing oxygen, such as indium tin oxide, indium oxidecontaining tungsten oxide, indium zinc oxide containing tungsten oxide,indium oxide containing titanium oxide, indium tin oxide containingtitanium oxide, indium zinc oxide, or indium tin oxide to which siliconoxide is added. It is also possible to use a stacked-layer structureformed using the above conductive material containing oxygen and amaterial containing the above metal element.

The terminal electrode 116 may have a single-layer structure or astacked-layer structure of two or more layers. For example, asingle-layer structure of an aluminum layer containing silicon, atwo-layer structure in which a titanium layer is stacked over analuminum layer, a two-layer structure in which a titanium layer isstacked over a titanium nitride layer, a two-layer structure in which atungsten layer is stacked over a titanium nitride layer, a two-layerstructure in which a tungsten layer is stacked over a tantalum nitridelayer, and a three-layer structure in which a titanium layer, analuminum layer, and a titanium layer are stacked in this order aregiven. Alternatively, a layer, an alloy layer, or a nitride layercontaining aluminum and one or more elements selected from titanium,tantalum, tungsten, molybdenum, chromium, neodymium, and scandium may beused.

<Electrode 115>

The electrode 115 is preferably formed using a conductive material thatefficiently reflects light emitted from the EL layer 117 formed later.Note that the electrode 115 may have a stacked-layer structure of aplurality of layers without limitation to a single-layer structure. Forexample, in the case where the electrode 115 is used as an anode, alayer in contact with the EL layer 117 may be a light-transmittinglayer, such as an indium tin oxide layer, having a work function higherthan that of the EL layer 117 and a layer having high reflectance (e.g.,aluminum, an alloy containing aluminum, or silver) may be provided incontact with the layer.

The light-emitting device having a top emission structure is describedas an example in this embodiment. In the case of a light-emitting devicehaving a bottom emission structure or a dual emission structure, theelectrode 115 may be formed using a light-transmitting conductivematerial.

<Partition>

The partition 114 is provided in order to prevent an electrical shortcircuit between the adjacent electrodes 118. In the case of using ametal mask for formation of the EL layer 117 described later, thepartition 114 has a function of preventing the contact of metal maskwith a region where the light-emitting element 125 is formed. Thepartition 114 can be formed of an organic resin material such as anepoxy resin, an acrylic resin, or an imide resin or an inorganicmaterial such as silicon oxide. The partition 114 is preferably formedso that its sidewall has a tapered shape or a tilted surface with acontinuous curvature. The sidewall of the partition 114 having theabove-described shape enables favorable coverage with the EL layer 117and the electrode 118 formed later.

<EL Layer>

A structure of the EL layer 117 is described in Embodiment 9.

<Electrode 118>

The electrode 118 is used as a cathode in this embodiment, and thus ispreferably formed using a material that has a low work function and caninject electrons into the EL layer 117 described later. As well as asingle-layer of a metal having a low work function, a stack in which ametal material such as aluminum, a conductive oxide material such asindium tin oxide, or a semiconductor material is formed over aseveral-nanometer-thick buffer layer formed of an alkali metal or analkaline earth metal having a low work function may be used as theelectrode 118. As the buffer layer, an oxide of an alkaline earth metal,a halide, a magnesium-silver alloy, or the like can also be used.

In the case where light emitted from the EL layer 117 is extractedthrough the electrode 118, the electrode 118 preferably has a propertyof transmitting visible light.

<Bonding Layers>

The bonding layer 120 is in contact with the electrode 118 in thisembodiment. The substrate 121 is fixed by the bonding layer 120. Thebonding layer 112 is in contact with the separation layer 113. Thesubstrate 111 is fixed by the bonding layer 112. A light curableadhesive, a reaction curable adhesive, a thermosetting adhesive, or ananaerobic adhesive can be used as the bonding layer 120 and the bondinglayer 112. For example, an epoxy resin, an acrylic resin, or an imideresin can be used. A drying agent (e.g., zeolite) having a size lessthan or equal to the wavelength of light or a filler (e.g., titaniumoxide or zirconium) with a high refractive index is preferably mixedinto the bonding layer 120 in the case of a top emission structure orinto the bonding layer 112 in the case of a bottom emission structure,in which case the efficiency of extracting light emitted from the ELlayer 117 can be improved.

<Separation Layer>

The separation layer 113 can be formed using an element selected fromtungsten, molybdenum, titanium, tantalum, niobium, nickel, cobalt,zirconium, ruthenium, rhodium, palladium, osmium, iridium, and silicon;an alloy material containing any of the elements; or a compound materialcontaining any of the elements. The separation layer 113 can also beformed to have a single-layer structure or a stacked-layer structureusing any of the materials. Note that the crystalline structure of theseparation layer 113 may be amorphous, microcrystalline, orpolycrystalline. The separation layer 113 can also be formed using ametal oxide such as aluminum oxide, gallium oxide, zinc oxide, titaniumdioxide, indium oxide, indium tin oxide, indium zinc oxide, or InGaZnO(IGZO).

The separation layer 113 can be formed by a sputtering method, a CVDmethod, a coating method, a printing method, or the like. Note that thecoating method includes a spin coating method, a droplet dischargemethod, and a dispensing method.

In the case where the separation layer 113 has a single-layer structure,the separation layer 113 is preferably formed using tungsten,molybdenum, or a tungsten-molybdenum alloy. Alternatively, theseparation layer 113 is preferably formed using an oxide or oxynitrideof tungsten, an oxide or oxynitride of molybdenum, or an oxide oroxynitride of a tungsten-molybdenum alloy.

In the case where the separation layer 113 has a stacked-layer structureincluding, for example, a layer containing tungsten and a layercontaining an oxide of tungsten, the layer containing an oxide oftungsten may be formed as follows: the layer containing tungsten isformed first and then an insulating oxide layer is formed in contacttherewith, so that the layer containing an oxide of tungsten is formedat the interface between the layer containing tungsten and theinsulating oxide layer. Alternatively, the layer containing an oxide oftungsten may be formed by performing thermal oxidation treatment, oxygenplasma treatment, treatment with a highly oxidizing solution such asozone water, or the like on the surface of the layer containingtungsten.

<Anisotropic Conductive Connection Layer>

The anisotropic conductive connection layer 123 can be formed using anyof various kinds of anisotropic conductive films (ACF), anisotropicconductive pastes (ACP), and the like.

The anisotropic conductive connection layer 123 is formed by curing apaste-form or sheet-form material that is obtained by mixing conductiveparticles to a thermosetting resin or a thermosetting, light curableresin. The anisotropic conductive connection layer 123 exhibits ananisotropic conductive property by light irradiation orthermocompression bonding. As the conductive particles used for theanisotropic conductive connection layer 123, for example, particles of aspherical organic resin coated with a thin-film metal such as Au, Ni, orCo can be used.

<Method for Manufacturing Light-Emitting Device>

Next, a method for manufacturing the light-emitting device 100 isdescribed with reference to FIGS. 2A to 2E, FIGS. 3A to 3C, FIGS. 4A and4B, FIGS. 5A and 5B, and FIGS. 6A and 6B. FIGS. 2A to 6B arecross-sectional views taken along the dashed-dotted line A1-A2 in FIG.1A.

<Formation of Separation Layer>

First, the separation layer 113 is formed over an element formationsubstrate 101 (see FIG. 2A). Note that the element formation substrate101 may be a glass substrate, a quartz substrate, a sapphire substrate,a ceramic substrate, a metal substrate, or the like. Alternatively, theelement formation substrate 101 may be a plastic substrate having heatresistance to the processing temperature in this embodiment.

As the glass substrate, for example, a glass material such asaluminosilicate glass, aluminoborosilicate glass, or barium borosilicateglass is used. Note that when the glass substrate contains a largeamount of barium oxide (BaO), the glass substrate can be heat-resistantand more practical. Alternatively, crystallized glass or the like may beused.

In this embodiment, the separation layer 113 is formed of tungsten by asputtering method.

<Formation of Base Layer>

Next, the base layer 119 is formed over the separation layer 113 (seeFIG. 2A). In this embodiment, the base layer 119 is formed of siliconoxide by a plasma CVD method.

<Formation of Terminal Electrode>

Next, the terminal electrode 116 is formed over the base layer 119.First, a three-layer metal film in which aluminum is interposed betweentwo layers of molybdenum is formed over the base layer 119 by asputtering method. After that, a resist mask is formed over the metalfilm, and the metal film is etched into a desired shape with the use ofthe resist mask. In the above-described manner, the terminal electrode116 can be formed. The resist mask can be formed by a photolithographymethod, a printing method, an inkjet method, or the like as appropriate.Formation of the resist mask by an inkjet method needs no photomask;thus, manufacturing costs can be reduced.

The metal film may be etched by either a dry etching method or a wetetching method, or by both a dry etching method and a wet etchingmethod. In the case where the metal film is etched by a wet etchingmethod, a solution obtained by mixing phosphoric acid, acetic acid, andnitric acid, a solution containing oxalic acid, a solution containingphosphoric acid, or the like can be used as an etchant. After theetching treatment, the resist mask is removed (see FIG. 2B).

<Formation of Electrode 115>

Next, the electrode 115 is formed over the base layer 119. The electrode115 can be formed in a manner similar to that of the terminal electrode116. In this embodiment, the electrode 115 is formed using a material inwhich indium tin oxide is stacked over silver. The electrode 115 and theterminal electrode 116 are electrically connected to each other (seeFIG. 2B).

<Formation of Partition>

Next, the partition 114 is formed (see FIG. 2C). In this embodiment, thepartition 114 is formed in such a manner that a photosensitive organicresin material is applied by a coating method and processed into adesired shape. In this embodiment, the partition 114 is formed using aphotosensitive imide resin.

<Formation of EL Layer>

Next, the EL layer 117 is formed over the electrode 115 and thepartition 114 (see FIG. 2D).

<Formation of Electrode 118>

Next, the electrode 118 is formed in contact with the EL layer 117. Theelectrode 118 can be formed by an evaporation method, a sputteringmethod, or the like (see FIG. 2E).

<Formation of Substrate>

Next, the substrate 121 having the opening 122 a is formed over theelectrode 118 with the bonding layer 120 provided therebetween. At thistime, the opening 122 a of the substrate 121 is positioned so as tooverlap the terminal electrode 116. The bonding layer 120 has theopening 122 b that the opening 122 a overlaps. As described above, theopening 122 a and the opening 122 b are collectively called the opening122 in this specification (see FIG. 3A).

<Formation of Embedded Layer>

Next, an embedded layer 109 is formed in the opening 122 (see FIG. 3B).In the case where the embedded layer 109 is not formed in the opening122, a region of the terminal electrode 116 that the opening 122overlaps might be damaged at the time of separation of the elementformation substrate 101 performed later. Note that the embedded layer109 is removed later, and thus is preferably formed using a materialthat is soluble in water or an organic solvent. As such a material, asoluble resin such as a soluble acrylic resin, a soluble polyimideresin, or a soluble epoxy resin can be used. In addition, it ispreferable that the level of a surface of the embedded layer 109 besubstantially the same as that of a surface of the substrate 121. Asoluble acrylic resin is used as the embedded layer 109 in thisembodiment.

<Formation of Transfer Substrate>

Next, a transfer substrate 102 is attached onto the substrate 121 (seeFIG. 3C). The transfer substrate 102 is removed later, and thus can beformed of a UV tape or a dicing tape whose adhesion is reduced byirradiation with ultraviolet light, a tape whose adhesion is reduced byheating, or a low-viscosity tape. In this embodiment, a UV tape is usedas the transfer substrate 102.

<Separation of Substrate>

Next, the element formation substrate 101 and the separation layer 113are separated from the base layer 119 (see FIG. 4A). As a separationmethod, mechanical force (a separation process with a human hand or agripper, a separation process by rotation of a roller, ultrasonic waves,or the like) may be used. For example, a cut is made in the separationlayer 113 with a sharp edged tool, by laser light irradiation, or thelike and water is injected into the cut. A portion between theseparation layer 113 and the base layer 119 absorbs water throughcapillarity action, so that the element formation substrate 101 can beseparated easily.

<Attachment of Light-Emitting Device and Substrate>

Next, the substrate 111 is attached to the base layer 119 with thebonding layer 112 provided therebetween (see FIG. 4B).

<Separation of Transfer Substrate>

Next, the transfer substrate 102 is separated. The transfer substrate102 is formed of a UV tape in this embodiment. Thus, by irradiation withultraviolet light 103 (see FIG. 5A), the transfer substrate 102 can beseparated easily (see FIG. 5B).

<Removal of Embedded Layer>

Next, the embedded layer 109 is removed with a solvent that is suitablefor removal of the embedded layer 109, such as water or an organicsolvent (see FIG. 6A).

<Formation of External Electrode>

Next, the anisotropic conductive connection layer 123 is formed in theopening 122. In addition, the external electrode 124 for inputtingelectric power or a signal to the light-emitting device 100 is formed atthe position over the opening 122, which overlaps the terminal electrode116 (see FIG. 6B). The external electrode 124 is electrically connectedto the terminal electrode 116 through the anisotropic conductiveconnection layer 123. Thus, electric power or a signal can be input tothe light-emitting device 100. Note that an FPC can be used as theexternal electrode 124.

Note that a metal wire can also be used as the external electrode 124.The metal wire and the terminal electrode 116 can be connected to eachother by a wire bonding method without using the anisotropic conductiveconnection layer 123. Alternatively, the metal wire and the terminalelectrode 116 can be connected to each other by a soldering method.

In one embodiment of the present invention, removal of part of thesubstrate 121 by laser light or with an edged tool for inputtingelectric power or a signal to the light-emitting device 100 is notneeded; thus, the light-emitting device 100 and the terminal electrode116 are not easily damaged. One embodiment of the present invention canprovide a highly reliable light-emitting device having highmanufacturing yield.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 2

In this embodiment, a method for manufacturing the light-emitting device100, which is different from the method disclosed in Embodiment 1, isdescribed. Note that description is made mainly on portions differentfrom those in Embodiment 1 to avoid repeated description.

<Method for Manufacturing Light-Emitting Device>

The manufacturing method can be performed in a manner similar to thatdescribed in Embodiment 1 until the formation of the partition 114 (seeFIG. 2C).

<Formation of EL Layer>

Next, the EL layer 117 is formed over the electrode 115 and thepartition 114. At the same time as the EL layer 117, a layer 104 isformed in a region on the terminal electrode 116 that the opening 122 isto overlap (see FIG. 7A). The layer 104 can be formed using a materialand a method similar to those of the EL layer 117.

<Formation of Electrode 118>

Next, the electrode 118 is formed in contact with the EL layer 117. Atthis time, a layer 105 is formed in a region on the layer 104 that theopening 122 is to overlap. The layer 105 can be formed using part of alayer formed at the same time as the electrode 118 (see FIG. 7B).

<Formation of Substrate 121>

Next, the substrate 121 is formed over the electrode 118 with thebonding layer 120 provided therebetween. At this time, the opening 122of the substrate 121 is positioned so as to overlap the terminalelectrode 116, the layer 105, and the layer 104 (see FIG. 7C). Note thatthe bonding layer 120 is not formed in a region that the opening 122overlaps, which means that the bonding layer 120 also has an openingthat the opening 122 overlaps.

Note that the layer 104 is formed to have a size with which the outeredge of the layer 104 is located outside the opening of the bondinglayer when seen from the top. In addition, the layer 105 is formed tohave a size with which the outer edge of the layer 105 is located insidethe opening of the bonding layer when seen from the top.

<Formation of Embedded Layer and Transfer Substrate>

Next, the embedded layer 109 and the transfer substrate 102 are eachformed in a manner similar to that in Embodiment 1 (see FIG. 7D). Then,the element formation substrate 101 is separated, and the substrate 111is attached to the base layer 119 with the bonding layer 112 providedtherebetween.

<Separation of Transfer Substrate>

Next, the transfer substrate 102 is irradiated with ultraviolet light103 to weaken the adhesion of the transfer substrate 102, so that thetransfer substrate 102 is separated. Before the irradiation with theultraviolet light 103, a mask 107 is provided in a region of thetransfer substrate 102 that overlaps the embedded layer 109 in order toprevent irradiation of the region with the ultraviolet light 103 (seeFIG. 8A).

By providing the mask 107 in the above-described manner, the adhesion ofthe region of the transfer substrate 102 that overlaps the embeddedlayer 109 is maintained without being reduced. Since the adhesion of theinterface between the layer 104 and the layer 105 is low, the embeddedlayer 109 and the layer 105 can also be removed at the time of theseparation of the transfer substrate 102 (see FIG. 8B).

<Removal of Layer 104>

Next, the layer 104 is removed with an organic solvent such as ethylalcohol to expose part of a surface of the terminal electrode 116 (seeFIG. 9A).

<Formation of External Electrode>

Next, the anisotropic conductive connection layer 123 is formed in theopening 122, and the external electrode 124 for inputting electric poweror a signal to the light-emitting device 100 is formed over theanisotropic conductive connection layer 123 (see FIG. 9B). The externalelectrode 124 and the terminal electrode 116 are electrically connectedto each other through the anisotropic conductive connection layer 123.Thus, electric power or a signal can be supplied or input to thelight-emitting device 100. Note that an FPC can be used as the externalelectrode 124.

In one embodiment of the present invention, removal of part of thesubstrate 121 for inputting electric power or a signal to thelight-emitting device 100 is not needed; thus, the light-emitting device100 and the terminal electrode 116 are not easily damaged. Oneembodiment of the present invention can provide a highly reliablelight-emitting device having high manufacturing yield.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 3

In this embodiment, a light-emitting device 200 having a structuredifferent from the structure of the light-emitting device 100 describedin the above embodiment is described with reference to FIGS. 10A and10B. FIG. 10A is a top view of the light-emitting device 200, and FIG.10B is a cross-sectional view taken along the dashed-dotted line B1-B2in FIG. 10A.

<Structure of Light-Emitting Device>

The light-emitting device 200 described in this embodiment includes adisplay area 231 and a peripheral circuit 251. The light-emitting device200 also includes a terminal electrode 216 and the light-emittingelement 125 including the electrode 115, the EL layer 117, and theelectrode 118. A plurality of light-emitting elements 125 are formed inthe display area 231. A transistor 232 for controlling the amount oflight emitted from the light-emitting element 125 is connected to eachlight-emitting element 125.

The terminal electrode 216 is electrically connected to the externalelectrode 124 through the anisotropic conductive connection layer 123formed in the opening 122. In addition, the terminal electrode 216 iselectrically connected to the peripheral circuit 251.

The peripheral circuit 251 includes a plurality of transistors 252. Theperipheral circuit 251 has a function of determining which of thelight-emitting elements 125 in the display area 231 is supplied with asignal from the external electrode 124.

In the light-emitting device 200 illustrated in FIGS. 10A and 10B, thesubstrate 111 and the substrate 121 are attached to each other with thebonding layer 120 provided therebetween. An insulating layer 205 isformed over the substrate 111 with the bonding layer 112 providedtherebetween. The insulating layer 205 is preferably formed as a singlelayer or a multilayer using any of silicon oxide, silicon nitride,silicon oxynitride, silicon nitride oxide, aluminum oxide, aluminumoxynitride, and aluminum nitride oxide. The insulating layer 205 can beformed by a sputtering method, a CVD method, a thermal oxidation method,a coating method, a printing method, or the like.

Note that the insulating layer 205 functions as a base layer and canprevent or reduce diffusion of impurity elements from the substrate 111,the bonding layer 112, or the like to the transistor or thelight-emitting element.

In addition, the transistor 232, the transistor 252, the terminalelectrode 216, and a wiring 219 are formed over the insulating layer205. Note that although a channel-etched transistor that is a type ofbottom-gate transistor is illustrated as the transistor 232 and thetransistor 252 in this embodiment, a channel-protective transistor, atop-gate transistor, or the like can also be used. It is also possibleto use a dual-gate transistor, in which a semiconductor layer in which achannel is formed is interposed between two gate electrodes.

The transistor 232 and the transistor 252 may have the same structure.However, the size (e.g., channel length and channel width) or the likeof each transistor can be adjusted as appropriate.

The transistor 232 and the transistor 252 each include a gate electrode206, a gate insulating layer 207, a semiconductor layer 208, a sourceelectrode 209 a, and a drain electrode 209 b.

The terminal electrode 216, the wiring 219, the gate electrode 206, thesource electrode 209 a, and the drain electrode 209 b can be formedusing a material and a method similar to those of the terminal electrode116. In addition, the gate insulating layer 207 can be formed using amaterial and a method similar to those of the insulating layer 205.

The semiconductor layer 208 can be formed using an amorphoussemiconductor, a microcrystalline semiconductor, a polycrystallinesemiconductor, or the like. For example, amorphous silicon ormicrocrystalline germanium can be used. Alternatively, a compoundsemiconductor such as silicon carbide, gallium arsenide, an oxidesemiconductor, or a nitride semiconductor, an organic semiconductor, orthe like can be used.

Note that an oxide semiconductor has an energy gap as wide as 3.0 eV ormore and high visible-light transmissivity. In a transistor obtained byprocessing an oxide semiconductor under appropriate conditions, theoff-state current at ambient temperature (e.g., 25° C.) can be less thanor equal to 100 zA (1×10⁻¹⁹ A), less than or equal to 10 zA (1×10⁻²⁰ A),and further less than or equal to 1 zA (1×10⁻²¹ A). Therefore, alight-emitting device with low power consumption can be achieved.

In the case where an oxide semiconductor is used for the semiconductorlayer 208, an insulating layer containing oxygen is preferably used asan insulating layer that is in contact with the semiconductor layer 208.

In addition, an insulating layer 210 is formed over the transistor 232and the transistor 252, and an insulating layer 211 is formed over theinsulating layer 210. The insulating layer 210 functions as a protectiveinsulating layer and can prevent or reduce diffusion of impurityelements from a layer above the insulating layer 210 to the transistor232 and the transistor 252. The insulating layer 210 can be formed usinga material and a method similar to those of the insulating layer 205.

Planarization treatment may be performed on the insulating layer 211 toreduce unevenness of a surface on which the light-emitting element 125is formed. The planarization treatment may be, but not particularlylimited to, polishing treatment (e.g., chemical mechanical polishing(CMP)) or dry etching treatment.

Forming the insulating layer 211 using an insulating material with aplanarization function can omit polishing treatment. As the insulatingmaterial with a planarization function, for example, an organic materialsuch as a polyimide resin or an acrylic resin can be used. Other thanthe above-described organic materials, it is also possible to use alow-dielectric constant material (low-k material) or the like. Note thatthe insulating layer 211 may be formed by stacking a plurality ofinsulating films formed of these materials.

In addition, over the insulating layer 211, the light-emitting element125 and the partition 114 for separating the adjacent light-emittingelements 125 are formed.

In addition, the substrate 121 is provided with a light-shielding film264, a coloring layer 266, and an overcoat layer 268. The light-emittingdevice 200 is a top-emission light-emitting device, in which lightemitted from the light-emitting element 125 is extracted from thesubstrate 121 side through the coloring layer 266.

The light-emitting element 125 is electrically connected to thetransistor 232 through openings formed in the insulating layer 211 andthe insulating layer 210.

Although an active matrix light-emitting device is described as anexample of the light-emitting device in this embodiment, the presentinvention can also be applied to a passive matrix light-emitting device.

One embodiment of the present invention can be applied to displaydevices such as a liquid crystal display device including a liquidcrystal element as a display element, an electronic paper, a digitalmicromirror device (DMD), a plasma display panel (PDP), a field emissiondisplay (FED), and a surface-conduction electron-emitter display (SED),without limitation to a light-emitting device including a light-emittingelement as a display element.

An example of a liquid crystal element is an element that controlstransmission and non-transmission of light by optical modulation actionof a liquid crystal. The element can include a pair of electrodes and aliquid crystal layer. Note that optical modulation action of a liquidcrystal is controlled by an electric field applied to the liquid crystal(including a horizontal electric field, a vertical electric field, andan oblique electric field). The following are specific examples of theliquid crystal: nematic liquid crystal, cholesteric liquid crystal,smectic liquid crystal, discotic liquid crystal, thermotropic liquidcrystal, lyotropic liquid crystal, low-molecular liquid crystal, polymerliquid crystal, polymer dispersed liquid crystal (PDLC), ferroelectricliquid crystal, anti-ferroelectric liquid crystal, main-chain liquidcrystal, side-chain polymer liquid crystal, and banana-shaped liquidcrystal. Moreover, the following methods can be employed for driving theliquid crystal: a twisted nematic (TN) mode, a super twisted nematic(STN) mode, an in-plane-switching (IPS) mode, a fringe field switching(FFS) mode, a multi-domain vertical alignment (MVA) mode, a patternedvertical alignment (PVA) mode, an advanced super view (ASV) mode, anaxially symmetric aligned microcell (ASM) mode, an optically compensatedbirefringence (OCB) mode, an electrically controlled birefringence (ECB)mode, an ferroelectric liquid crystal (FLC) mode, an anti-ferroelectricliquid crystal (AFLC) mode, a polymer dispersed liquid crystal (PDLC)mode, a polymer network liquid crystal (PNLC) mode, a guest-host mode,and a blue phase mode. Note that the present invention is not limited tothese examples and any of a variety of liquid crystal elements anddriving methods can be applied to the liquid crystal element and thedriving method thereof.

Display of electronic paper can be performed using, for example,molecules (a method utilizing optical anisotropy, dye molecularorientation, or the like), particles (a method utilizingelectrophoresis, particle movement, particle rotation, phase change, orthe like), movement of one end of a film, coloring properties or phasechange of molecules, optical absorption by molecules, or self-lightemission by combination of electrons and holes. Specific examples of adisplay method of electronic paper include microcapsule electrophoresis,horizontal electrophoresis, vertical electrophoresis, a sphericaltwisting ball, a magnetic twisting ball, a columnar twisting ball, acharged toner, electronic liquid powder, magnetic electrophoresis, amagnetic thermosensitive type, electro wetting, light-scattering(transparent-opaque change), a cholesteric liquid crystal and aphotoconductive layer, cholesteric liquid crystal, bistable nematicliquid crystal, ferroelectric liquid crystal, a liquid crystal dispersedtype with a dichroic dye, a movable film, coloring and decoloringproperties of a leuco dye, photochromism, electrochromism,electrodeposition, and flexible organic EL. Note that the presentinvention is not limited to these examples, and various electronic paperand display methods can be used as electronic paper and a display methodthereof. Here, with the use of microcapsule electrophoresis, aggregationand precipitation of phoresis particles can be prevented. Electronicliquid powder has advantages such as high-speed response, highreflectivity, wide viewing angle, low power consumption, and memoryproperties.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 4

A structure example of a light-emitting device 2100 of one embodiment ofthe present invention is described with reference to FIGS. 11A and 11Band FIG. 12. FIG. 11A is a perspective view illustrating an outerappearance of the light-emitting device 2100, and FIG. 11B is a top viewof the light-emitting device 2100. FIG. 12 is a cross-sectional viewtaken along the dashed-dotted line C1-C2 in FIG. 11A. Note that thelight-emitting device 2100 disclosed in this specification is a displaydevice in which a light-emitting element is used as a display element.

<Structure of Light-Emitting Device>

The light-emitting device 2100 described in this embodiment includes anelectrode 2115, an EL layer 2117, an electrode 2118, a partition 2114,and a terminal electrode 2116. The electrode 2115 and the terminalelectrode 2116 are electrically connected to each other. In thelight-emitting device 2100, the partition 2114 is provided over theelectrode 2115, the EL layer 2117 is provided over the electrode 2115and the partition 2114, and the electrode 2118 is provided over the ELlayer 2117.

A light-emitting element 2125 includes the electrode 2115, the EL layer2117, and the electrode 2118. The light-emitting element 2125 is formedover a substrate 2111 with a bonding layer 2112 and a base layer 2119provided therebetween. Note that a plurality of light-emitting elements2125 are provided in a display area 2131.

In addition, in the light-emitting device 2100 described in thisembodiment, a substrate 2121 is formed over the electrode 2118 with abonding layer 2120 provided therebetween.

The base layer 2119 has an opening 2122 a that the terminal electrode2116 overlaps. The bonding layer 2112 and the substrate 2111 have anopening 2122 b that the opening 2122 a overlaps. In this specification,the opening 2122 a and the opening 2122 b are collectively called anopening 2122. An external electrode 2124 and the terminal electrode 2116are electrically connected to each other through an anisotropicconductive connection layer 2123 in the opening 2122.

A switching element for controlling a signal supplied to thelight-emitting element 2125 may be provided between the light-emittingelement 2125 and the terminal electrode 2116. For example, a transistormay be provided between the light-emitting element 2125 and the terminalelectrode 2116.

A transistor is a kind of semiconductor element and enablesamplification of current or voltage, switching operation for controllingconduction or non-conduction, or the like. By providing a transistorbetween the light-emitting element 2125 and the terminal electrode 2116,the area of the display area 2131 can be increased easily and ahigher-resolution display can be achieved easily. Note that withoutlimitation to a switching element such as a transistor, a resistor, aninductor, a capacitor, or the like can be provided in the display area2131.

<Substrates>

The substrate 2121 and the substrate 2111 can be formed using materialssimilar to those of the substrate 121 and the substrate 111 disclosed inthe above embodiment. In the case where the light-emitting device 2100is a bottom-emission light-emitting device or a dual-emissionlight-emitting device, a material that transmits light emitted from theEL layer 2117 is used for the substrate 2111. In the case where thelight-emitting device 2100 is a top-emission light-emitting device or adual-emission light-emitting device, a material that transmits lightemitted from the EL layer 2117 is used for the substrate 2121.

<Base Layer>

The base layer 2119 can be formed using a material and a method similarto those of the base layer 119 disclosed in the above embodiment.

The base layer 2119 can prevent or reduce diffusion of impurity elementsfrom the substrate 2111, the bonding layer 2112, or the like to thelight-emitting element 2125.

<Terminal Electrode>

The terminal electrode 2116 can be formed using a material and a methodsimilar to those of the terminal electrode 116 disclosed in the aboveembodiment.

<Electrode 2115>

The electrode 2115 is preferably formed using a conductive material thatefficiently reflects light emitted from the EL layer 2117 formed later.The electrode 2115 can be formed using a material and a method similarto those of the electrode 115 disclosed in the above embodiment.

The light-emitting device having a top emission structure is describedas an example in this embodiment. In the case of a light-emitting devicehaving a bottom emission structure or a dual emission structure, theelectrode 2115 may be formed using a light-transmitting conductivematerial.

<Partition>

The partition 2114 is provided in order to prevent an electrical shortcircuit between the adjacent electrodes 2118. In the case of using ametal mask for formation of the EL layer 2117 described later, thepartition 2114 has a function of preventing contact of the metal maskwith a region where the light-emitting element 2125 is formed. Thepartition 2114 can be formed using a material and a method similar tothose of the partition 114 disclosed in the above embodiment. Thepartition 2114 is preferably formed so that its sidewall has a taperedshape or a tiled surface with a continuous curvature. The sidewall ofthe partition 2114 having the above-described shape enables favorablecoverage with the EL layer 2117 and the electrode 2118 formed later.

<EL Layer>

A structure of the EL layer 2117 is described in Embodiment 9.

<Electrode 2118>

The electrode 2118 is used as a cathode in this embodiment, and thus ispreferably formed using a material that has a low work function and caninject electrons into the EL layer 2117 described later. The electrode2118 can be formed using a material and a method similar to those of theelectrode 118 disclosed in the above embodiment.

In the case where light emitted from the EL layer 2117 is extractedthrough the electrode 2118, the electrode 2118 preferably has a propertyof transmitting visible light.

<Bonding Layers>

The bonding layer 2120 is in contact with the electrode 2118 in thisembodiment. The substrate 2121 is fixed by the bonding layer 2120. Thebonding layer 2112 is in contact with the base layer 2119. The substrate2111 is fixed by the bonding layer 2112. The bonding layer 2120 and thebonding layer 2112 can be formed using a material and a method similarto those of the bonding layer 120 and the bonding layer 112 disclosed inthe above embodiment. A drying agent (e.g., zeolite) having a size lessthan or equal to the wavelength of light or a filler (e.g., titaniumoxide or zirconium) with a high refractive index is preferably mixedinto the bonding layer 2120 in the case of a top emission structure orinto the bonding layer 2112 in the case of a bottom emission structure,in which case the efficiency of extracting light emitted from the ELlayer 2117 can be improved.

<Anisotropic Conductive Connection Layer>

The anisotropic conductive connection layer 2123 can be formed using amaterial and a method similar to those of the anisotropic conductiveconnection layer 123 disclosed in the above embodiment.

<Method for Manufacturing Light-Emitting Device>

Next, an example of a method for manufacturing the light-emitting device2100 is described with reference to FIGS. 13A to 13D, FIGS. 14A to 14D,and FIGS. 15A to 15C. FIGS. 13A to 15C are cross-sectional views takenalong the dashed-dotted line C1-C2 in FIGS. 11A and 11B.

<Formation of Separation Layer>

First, a separation layer 2113 is formed over an element formationsubstrate 2101 (see FIG. 13A). Note that the element formation substrate2101 can be formed using a material similar to that of the elementformation substrate 101 disclosed in the above embodiment.

The separation layer 2113 can be formed using a material and a methodsimilar to those of the separation layer 113 disclosed in the aboveembodiment.

In this embodiment, the separation layer 2113 is formed of tungsten by asputtering method.

<Formation of Base Layer>

Next, the base layer 2119 is formed over the separation layer 2113 (seeFIG. 13A). In this embodiment, the base layer 2119 is formed of siliconoxide by a plasma CVD method.

<Formation of Opening>

Next, part of the base layer 2119 is selectively removed to form theopening 2122 a (see FIG. 13B). Specifically, a resist mask is formedover the base layer 2119, and the part of the base layer 2119 isselectively etched with the use of the resist mask. The resist mask canbe formed by a photolithography method, a printing method, an inkjetmethod, or the like as appropriate. Formation of the resist mask by aninkjet method needs no photomask; thus, manufacturing costs can bereduced. The base layer 2119 may be etched by either a dry etchingmethod or a wet etching method, or by both a dry etching method and awet etching method. The base layer 2119 is preferably etched under thecondition that the etching rate of the base layer 2119 is higher thanthat of the separation layer 2113.

<Oxidation Treatment in Opening>

Next, a surface of the separation layer 2113 that is exposed because ofthe formation of the opening 2122 a is oxidized. The exposed surface ofthe separation layer 2113 can be oxidized by being in contact with asolution having oxidizability such as a hydrogen peroxide solution orwater containing ozone. Alternatively, the exposed surface of theseparation layer 2113 can be oxidized by being exposed to an oxygenatmosphere and furthermore being irradiated with ultraviolet light.Further alternatively, the exposed surface of the separation layer 2113may be exposed to oxygen plasma. In this embodiment, the surface of theseparation layer 2113 that is exposed because of the formation of theopening 2122 a is oxidized by being exposed to oxygen plasma 2126 (seeFIG. 13C).

Forming an oxide layer on the surface of the separation layer 2113 canfacilitate separation of the element formation substrate 2101 performedlater.

<Formation of Terminal Electrode>

Next, the terminal electrode 2116 overlapping the base layer 2119 andthe opening 2122 a is formed (see FIG. 13D). The terminal electrode 2116can be formed using a material and a method similar to those of theterminal electrode 116 disclosed in the above embodiment.

Note that the separation layer 2113 and the terminal electrode 2116 arein contact with each other in the opening 2122 a through the surface ofthe separation layer 2113 that is oxidized by the former oxidationtreatment. The oxide layer formed at the interface between theseparation layer 2113 and the terminal electrode 2116 can preventseparation of the terminal electrode 2116 with the separation layer 2113at the time of separation of the element formation substrate 2101performed later.

<Formation of Electrode 2115>

Next, the electrode 2115 is formed over the base layer 2119. Theelectrode 2115 can be formed in a manner similar to that of the terminalelectrode 2116. In this embodiment, the electrode 2115 is formed using amaterial in which indium tin oxide is stacked over silver. The electrode2115 and the terminal electrode 2116 are electrically connected to eachother (see FIG. 14A).

<Formation of Partition>

Next, the partition 2114 is formed (see FIG. 14B). In this embodiment,the partition 2114 is formed in such a manner that a photosensitiveorganic resin material is applied by a coating method and processed intoa desired shape. In this embodiment, the partition 2114 is formed usinga photosensitive imide resin.

<Formation of EL Layer>

Next, the EL layer 2117 is formed over the electrode 2115 and thepartition 2114 (see FIG. 14C).

<Formation of Electrode 2118>

Next, the electrode 2118 is formed so as to be in contact with the ELlayer 2117. The electrode 2118 can be formed by an evaporation method, asputtering method, or the like (see FIG. 14D).

<Formation of Substrate 2121>

Next, the substrate 2121 is formed over the electrode 2118 with thebonding layer 2120 provided therebetween (see FIG. 15A).

<Separation of Substrate>

Next, the element formation substrate 2101 and the separation layer 2113are separated from the base layer 2119 and the terminal electrode 2116(see FIG. 15B). The separation can be performed by a method similar tothe separation method of the substrate disclosed in the aboveembodiment.

<Attachment of Substrate to Light-Emitting Device>

Next, the substrate 2111 having the opening 2122 b is attached to thebase layer 2119 with the bonding layer 2112 provided therebetween (seeFIG. 15C). At this time, the opening 2122 b of the substrate 2111 ispositioned so that the opening 2122 b and the opening 2122 a overlap.The bonding layer 2112 is not formed in a region overlapping the opening2122 b. As described above, the opening 2122 a and the opening 2122 bare collectively called the opening 2122 in this specification.

<Formation of External Electrode>

Next, the anisotropic conductive connection layer 2123 is formed in theopening 2122. In addition, the external electrode 2124 for inputtingelectric power or a signal to the light-emitting device 2100 is formedat the position under the opening 2122, which the terminal electrode2116 overlaps (see FIG. 12). The external electrode 2124 is electricallyconnected to the terminal electrode 2116 through the anisotropicconductive connection layer 2123. Thus, electric power a signal can beinput to the light-emitting device 2100. Note that the externalelectrode 2124 can be formed using a material and a method similar tothose of the external electrode 124 disclosed in the above embodiment.

In one embodiment of the present invention, part of the substrate 2121does not need to be removed by laser light, with an edged tool, or thelike; thus, the display area 2131 and the terminal electrode 2116 arenot easily damaged. In addition, the distance between the display area2131 and the opening 2122 can be shortened; thus, signal attenuation orelectrical power attenuation can be suppressed. In addition, themanufacturing process is simplified; thus, the productivity of thelight-emitting device can be increased. One embodiment of the presentinvention can provide a highly reliable light-emitting device havinghigh manufacturing yield. In addition, one embodiment of the presentinvention can provide a light-emitting device with excellent displayquality.

Modification Example

One embodiment of the present invention can be a structure of alight-emitting device 2200 illustrated in FIGS. 16A and 16B. FIG. 16A isa perspective view illustrating an outer appearance of thelight-emitting device 2200, and FIG. 16B is a cross-sectional view takenalong the dashed-dotted line D1-D2 in FIG. 16A.

In the light-emitting device 2200, the shape of the substrate 2111 isdifferent from that in the light-emitting device 2100. The substrate2111 included in the light-emitting device 2200 does not have theopening 2122 b. In addition, the substrate 2111 is attached to the baselayer 2119 so that the substrate 2111 and the opening 2122 a overlap.Thus, the light-emitting device 2200 illustrated in FIGS. 16A and 16Bhas a structure in which edges of the substrate 2121 and the substrate2111 do not align.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 5

In this embodiment, a light-emitting device 2300 having a structuredifferent from the structure of the light-emitting device 2100 describedin the above embodiment is described with reference to FIGS. 17A and17B. FIG. 17A is a perspective view of the light-emitting device 2300,and FIG. 17B is a cross-sectional view taken along the dashed-dottedline E1-E2 in FIG. 17A.

<Structure of Light-Emitting Device>

The light-emitting device 2300 described in this embodiment includes adisplay area 2231 and a peripheral circuit 2251. The light-emittingdevice 2300 also includes a terminal electrode 2216 and thelight-emitting element 2125 including the electrode 2115, the EL layer2117, and the electrode 2118. A plurality of light-emitting elements2125 are formed in the display area 2231. A transistor 2232 forcontrolling the amount of light emitted from the light-emitting element2125 is connected to each light-emitting element 2125.

The terminal electrode 2216 is electrically connected to the externalelectrode 2124 through the anisotropic conductive connection layer 2123formed in the opening 2122. In addition, the terminal electrode 2216 iselectrically connected to the peripheral circuit 2251.

The peripheral circuit 2251 includes a plurality of transistors 2252.The peripheral circuit 2251 has a function of determining which of thelight-emitting elements 2125 in the display area 2231 is supplied with asignal from the external electrode 2124. Although a structure in whichfour peripheral circuits 2251 are provided outside the display area 2231is illustrated in FIG. 17A, one embodiment of the present invention isnot limited to the structure.

In the light-emitting device 2300 illustrated in FIGS. 17A and 17B, thesubstrate 2111 and the substrate 2121 are attached to each other withthe bonding layer 2120 provided therebetween. An insulating layer 2205is formed over the substrate 2111 with the bonding layer 2112 providedtherebetween. The insulating layer 2205 can be formed using a materialand a method similar to those of the insulating layer 205 disclosed inthe above embodiment.

Note that the insulating layer 2205 functions as a base layer and canprevent or reduce diffusion of impurity elements from the substrate2111, the bonding layer 2112, or the like to the transistor or thelight-emitting element.

In addition, the transistor 2232, the transistor 2252, the terminalelectrode 2216, and a wiring 2219 are formed over the insulating layer2205. Note that although a channel-etched transistor that is a type ofbottom-gate transistor is illustrated as the transistor 2232 and thetransistor 2252 in this embodiment, a channel-protective transistor, atop-gate transistor, or the like can also be used.

The transistor 2232 and the transistor 2252 have the same structure.However, the size (e.g., channel length and channel width) or the likeof each transistor can be adjusted as appropriate.

The transistor 2232 and the transistor 2252 each include a gateelectrode 2206, a gate insulating layer 2207, a semiconductor layer2208, a source electrode 2209 a, and a drain electrode 2209 b.

The terminal electrode 2216, the wiring 2219, the gate electrode 2206,the source electrode 2209 a, and the drain electrode 2209 b can beformed using a material and a method similar to those of the terminalelectrode 2116. In addition, the gate insulating layer 2207 can beformed using a material and a method similar to those of the insulatinglayer 2205.

The semiconductor layer 2208 can be formed using a material and a methodsimilar to those of the semiconductor layer 208 disclosed in the aboveembodiment.

In the case where an oxide semiconductor is used for the semiconductorlayer 2208, an insulating layer containing oxygen is preferably used asan insulating layer that is in contact with the semiconductor layer2208.

In addition, an insulating layer 2210 is formed over the transistor 2232and the transistor 2252, and an insulating layer 2211 is formed over theinsulating layer 2210. The insulating layer 2210 functions as aprotective insulating layer and can prevent or reduce diffusion ofimpurity elements from a layer above the insulating layer 2210 to thetransistor 2232 and the transistor 2252. The insulating layer 2210 canbe formed using a material and a method similar to those of theinsulating layer 2205.

Planarization treatment may be performed on the insulating layer 2211 toreduce unevenness of a surface on which the light-emitting element 2125is formed. The planarization treatment may be, but not particularlylimited to, polishing treatment (e.g., chemical mechanical polishing) ordry etching treatment.

Forming the insulating layer 2211 using an insulating material with aplanarization function can omit polishing treatment. As the insulatingmaterial with a planarization function, for example, an organic materialsuch as a polyimide resin or an acrylic resin can be used. Other thanthe above-described organic materials, it is also possible to use alow-dielectric constant material (low-k material) or the like. Note thatthe insulating layer 2211 may be formed by stacking a plurality ofinsulating films formed of these materials.

In addition, over the insulating layer 2211, the light-emitting element2125 and the partition 2114 for separating the adjacent light-emittingelements 2125 are formed.

In addition, the substrate 2121 is provided with a light-shielding film2264, a coloring layer 2266, and an overcoat layer 2268. Thelight-emitting device 2300 is a top-emission light-emitting device, inwhich light emitted from the light-emitting element 2125 is extractedfrom the substrate 2121 side through the coloring layer 2266.

The light-emitting element 2125 is electrically connected to thetransistor 2232 through openings formed in the insulating layer 2211 andthe insulating layer 2210.

Although an active matrix light-emitting device is described as anexample of the light-emitting device in this embodiment, the presentinvention can also be applied to a passive matrix light-emitting device.

One embodiment of the present invention can be applied to displaydevices such as a liquid crystal display device including a liquidcrystal element as a display element, an electronic paper, DMD, PDP,FED, and SED, without limitation to a light-emitting device including alight-emitting element as a display element.

Materials of a liquid crystal element can be similar to those given asexamples in the above embodiment. A driving method of a liquid crystalelement can be similar to any of the driving methods of the liquidcrystal element disclosed in the above embodiment.

A display method of an electronic paper can be similar to any of thedisplay methods of the electronic paper disclosed in the aboveembodiment.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 6

Structure examples of a light-emitting device 3100 of one embodiment ofthe present invention are described with reference to FIGS. 18A to 18D,FIGS. 19A to 19C, and FIGS. 20A and 20B. FIG. 18A is a perspective viewillustrating the light-emitting device 3100, and FIG. 18B is an enlargedview of a portion 3150 in FIG. 18A. FIGS. 18C and 18D arecross-sectional views taken along the dashed-dotted line F1-F2 in FIG.18A. Note that the light-emitting device 3100 disclosed in thisspecification is a display device in which a light-emitting element isused as a display element.

<Structure of Light-Emitting Device>

The light-emitting device 3100 described in this embodiment includes anelectrode 3115, an EL layer 3117, an electrode 3118, a partition 3114,and a terminal electrode 3116. The electrode 3115 and the terminalelectrode 3116 are electrically connected to each other. In thelight-emitting device 3100, the partition 3114 is provided over theelectrode 3115, the EL layer 3117 is provided over the electrode 3115and the partition 3114, and the electrode 3118 is provided over the ELlayer 3117.

A light-emitting element 3125 includes the electrode 3115, the EL layer3117, and the electrode 3118. The light-emitting element 3125 is formedover a substrate 3111 with a bonding layer 3112 and a base layer 3119provided therebetween. Note that a plurality of light-emitting elements3125 are provided in a display area 3131.

In addition, in the light-emitting device 3100 described in thisembodiment, a substrate 3121 is formed over the electrode 3118 with abonding layer 3120 provided therebetween.

The substrate 3121 has a groove 3141. Although the groove 3141illustrated in FIGS. 18A to 18C penetrate the substrate 3121 in thethickness direction, the groove 3141 does not necessarily penetrate thesubstrate 3121 in the thickness direction. As illustrated in FIG. 18D,the groove 3141 may have a given depth without penetrating the substrate3121. When the groove 3141 does not penetrate the substrate 3121, thedepth of the groove 3141 is preferably ½ or more, more preferably ⅔ ormore, of the thickness of the substrate 3121. Note that in a plan view,a region of the substrate 3121 that is surrounded with the groove 3141is called a portion 3121 a.

In addition, a layer 3104 is formed over the terminal electrode 3116,and a layer 3105 is formed over the layer 3104. The layer 3104 and thelayer 3105 over the terminal electrode 3116 are formed in a positionthat the portion 3121 a overlaps.

As illustrated in FIGS. 19A to 19C, the portion 3121 a and the bondinglayer 3120 that the portion 3121 a overlaps are separated from thelight-emitting device 3100, so that part of the terminal electrode 3116can be exposed. FIG. 19A is a perspective view illustrating part of aseparation step of the portion 3121 a and the bonding layer 3120 thatthe portion 3121 a overlaps. FIG. 19B is a perspective view illustratinga state after the separation step. FIG. 19C is a cross-sectional viewtaken along the dashed-dotted line F1-F2 in FIG. 19B.

The portion 3121 a and the bonding layer 3120 that the portion 3121 aoverlaps are removed to form an opening 3122, so that part of theterminal electrode 3116 can be exposed.

Providing the layer 3104 and the layer 3105 in positions that theportion 3121 a overlaps facilitates separation of the portion 3121 awith the bonding layer 3120 that the portion 3121 a overlaps, so thatthe terminal electrode 3116 can be exposed. Note that the layer 3104 andthe layer 3105 are described in detail later.

As illustrated in FIGS. 20A and 20B, an external electrode 3124 and theterminal electrode 3116 can be electrically connected to each otherthrough an anisotropic conductive connection layer 3123 in the opening3122. Thus, a region of the substrate 3121 that overlaps the opening3122 is also called an external electrode connection region. FIG. 20A isa perspective view of the light-emitting device 3100 to which theexternal electrode 3124 is connected, and FIG. 20B is a cross-sectionalview taken along the dashed-dotted line F1-F2 in FIG. 20A.

A switching element for controlling a signal supplied to thelight-emitting element 3125 may be provided between the light-emittingelement 3125 and the terminal electrode 3116. For example, a transistormay be provided between the light-emitting element 3125 and the terminalelectrode 3116.

A transistor is a kind of semiconductor element and enablesamplification of current or voltage, switching operation for controllingconduction or non-conduction, or the like. By providing a transistorbetween the light-emitting element 3125 and the terminal electrode 3116,the area of the display area 3131 can be increased easily and ahigher-resolution display can be achieved easily. Note that a resistor,an inductor, a capacitor, or the like, without limitation to a switchingelement such as a transistor, can be provided in the display area 3131.

<Substrates>

The substrate 3111 and the substrate 3121 can be formed using materialssimilar to those of the substrate 121 and the substrate 111 disclosed inthe above embodiment. In the case where the light-emitting device 3100is a bottom-emission light-emitting device or a dual-emissionlight-emitting device, a material that transmits light emitted from theEL layer 3117 is used for the substrate 3111. In the case where thelight-emitting device 3100 is a top-emission light-emitting device or adual-emission light-emitting device, a material that transmits lightemitted from the EL layer 3117 is used for the substrate 3121.

<Base Layer>

The base layer 3119 can be formed using a material and a method similarto those of the base layer 119 disclosed in the above embodiment.

The base layer 3119 can prevent or reduce diffusion of impurity elementsfrom the substrate 3111, the bonding layer 3112, or the like to thelight-emitting element 3125.

<Terminal Electrode>

The terminal electrode 3116 can be formed using a material and a methodsimilar to those of the terminal electrode 116 disclosed in the aboveembodiment.

<Electrode 3115>

The electrode 3115 is preferably formed using a conductive material thatefficiently reflects light emitted from the EL layer 3117 formed later.The electrode 3115 can be formed using a material and a method similarto those of the electrode 115 disclosed in the above embodiment.

The light-emitting device having a top emission structure is describedas an example in this embodiment. In the case of a light-emitting devicehaving a bottom emission structure or a dual emission structure, theelectrode 3115 may be formed using a light-transmitting conductivematerial.

<Partition>

The partition 3114 is provided in order to prevent an electrical shortcircuit between the adjacent electrodes 3118. In the case of using ametal mask for formation of the EL layer 3117 described later, thepartition 3114 also has a function of preventing the metal mask frombeing in contact with a region where the light-emitting element 3125 isformed. The partition 3114 can be formed using a material and a methodsimilar to those of the partition 114 disclosed in the above embodiment.The partition 3114 is preferably formed so that its sidewall has atapered shape or a tilted surface with a continuous curvature. Thesidewall of the partition 3114 having the above-described shape enablesfavorable coverage with the EL layer 3117 and the electrode 3118 formedlater.

<EL Layer>

A structure of the EL layer 3117 is described in Embodiment 9.

<Electrode 3118>

The electrode 3118 is used as a cathode in this embodiment, and thus ispreferably formed using a material that has a low work function and caninject electrons into the EL layer 3117 described later. The electrode3118 can be formed using a material and a method similar to those of theelectrode 118 disclosed in the above embodiment.

In the case where light emitted from the EL layer 3117 is extractedthrough the electrode 3118, the electrode 3118 preferably has a propertyof transmitting visible light.

<Bonding Layer>

The bonding layer 3120 is in contact with the electrode 3118 in thisembodiment. The substrate 3121 is fixed by the bonding layer 3120. Inaddition, the substrate 3111 is fixed by the bonding layer 3112. Thebonding layer 3120 and the bonding layer 3112 can be formed using amaterial and a method similar to those of the bonding layer 120 and thebonding layer 112 disclosed in the above embodiment. A drying agent(e.g., zeolite) having a size less than or equal to the wavelength oflight or a filler (e.g., titanium oxide or zirconium) with a highrefractive index is preferably mixed into the bonding layer 3120 in thecase of a top emission structure or into the bonding layer 3112 in thecase of a bottom emission structure, in which case the efficiency ofextracting light emitted from the EL layer 3117 can be improved.

<Anisotropic Conductive Connection Layer>

The anisotropic conductive connection layer 3123 can be formed using amaterial and a method similar to those of the anisotropic conductiveconnection layer 123 disclosed in the above embodiment.

<Method for Manufacturing Light-Emitting Device>

Next, an example of a method for manufacturing the light-emitting device3100 is described with reference to FIGS. 21A to 21E, FIGS. 22A and 22B,FIGS. 23A and 23B, and FIGS. 24A to 24C. FIGS. 21A to 24C arecross-sectional views taken along the dashed-dotted line F1-F2 in FIGS.18A and 18B, FIGS. 19A and 19B, and FIG. 20A.

<Formation of Separation Layer>

First, the separation layer 3113 is formed over an element formationsubstrate 3101 (see FIG. 21A). Note that the element formation substrate3101 can be formed using a material similar to that of the elementformation substrate 101 disclosed in the above embodiment.

The separation layer 3113 can be formed using a material and a methodsimilar to those of the separation layer 113 disclosed in the aboveembodiment.

In this embodiment, the separation layer 3113 is formed of tungsten by asputtering method.

<Formation of Base Layer>

Next, the base layer 3119 is formed over the separation layer 3113 (seeFIG. 21A). In this embodiment, the base layer 3119 is formed of siliconoxide by a plasma CVD method.

<Formation of Terminal Electrode>

Next, the terminal electrode 3116 is formed over the base layer 3119.First, a three-layer metal film in which aluminum is interposed betweentwo layers of molybdenum is formed over the base layer 3119 by asputtering method. After that, a resist mask is formed over the metalfilm, and the metal film is etched into a desired shape with the use ofthe resist mask. In the above-described manner, the terminal electrode3116 can be formed. The resist mask can be formed by a photolithographymethod, a printing method, an inkjet method, or the like as appropriate.Formation of the resist mask by an inkjet method needs no photomask;thus, manufacturing costs can be reduced.

The metal film may be etched by either a dry etching method or a wetetching method, or by both a dry etching method and a wet etchingmethod. In the case where the metal film is etched by a wet etchingmethod, a solution obtained by mixing phosphoric acid, acetic acid, andnitric acid, a solution containing oxalic acid, a solution containingphosphoric acid, or the like can be used as an etchant. After theetching treatment, the resist mask is removed (see FIG. 21B).

<Formation of Electrode>

Next, the electrode 3115 is formed over the base layer 3119. Theelectrode 3115 can be formed in a manner similar to that of the terminalelectrode 3116. In this embodiment, the electrode 3115 is formed using amaterial in which indium tin oxide is stacked over silver. The electrode3115 and the terminal electrode 3116 are electrically connected to eachother (see FIG. 21B).

<Formation of Partition>

Next, the partition 3114 is formed (see FIG. 21C). In this embodiment,the partition 3114 is formed in such a manner that a photosensitiveorganic resin material is applied by a coating method and processed intoa desired shape. In this embodiment, the partition 3114 is formed usinga photosensitive imide resin.

<Formation of EL Layer>

Next, the EL layer 3117 is formed over the electrode 3115 and thepartition 3114. At the same time as the EL layer 3117, the layer 3104 isformed in a region on the terminal electrode 3116 that the opening 3122is to overlap (see FIG. 21D). The layer 3104 can be formed using amaterial and a method similar to those of the EL layer 3117.

<Formation of Electrode>

Next, the electrode 3118 is formed in contact with the EL layer 3117. Atthe same time as the electrode 3118, the layer 3105 is formed in aregion on the layer 3104 that the opening 3122 is to overlap. The layer3105 can be formed using part of a layer formed at the same time as theelectrode 3118. The electrode 3118 and the layer 3105 can be formed byan evaporation method, a sputtering method, or the like (see FIG. 21E).

<Formation of Substrate>

Next, the substrate 3121 having the groove 3141 penetrating thesubstrate 3121 in the thickness direction is formed over the electrode3118 with the bonding layer 3120 provided therebetween. At this time,the substrate 3121 is formed so that the portion 3121 a of the substrate3121 overlaps the terminal electrode 3116, the layer 3104, and the layer3105 (see FIG. 22A).

Note that the layer 3104 is formed to have a size with which the outeredges of the layer 3104 are located outside the portion 3121 a when seenfrom the top. In addition, the layer 3105 is formed to have a size withwhich the outer edges of the layer 3105 are located inside the portion3121 a when seen from the top.

Note that in the case where the groove 3141 has a given depth, thegroove 3141 may be formed in such a manner that the substrate 3121without the groove 3141 is formed over the electrode 3118 first and thenthe groove 3141 is formed in the substrate 3121 with a sharp edged toolor by laser light.

If a sharp edged tool or laser light penetrates the substrate 3121 atthis time, the terminal electrode 3116 or another portion might bedamaged. For this reason, it is necessary that the groove 3141 does notpenetrate the substrate 3121 in the case where the groove 3141 is formedafter the substrate 3121 is formed over the electrode 3118.

Meanwhile, in the case where the formed groove 3141 is shallow, it isdifficult to separate the portion 3121 a in a later step. When thegroove 3141 does not penetrate the substrate 3121, the depth of thegroove 3141 is preferably ½ or more, more preferably ⅔ or more, of thethickness of the substrate 3121.

<Separation of Substrate>

Next, the element formation substrate 3101 and the separation layer 3113are separated from the base layer 3119 (see FIG. 22B). The separationcan be performed by a method similar to the separation method of thesubstrate disclosed in the above embodiment.

<Attachment of Substrate to Light-Emitting Device>

Next, the substrate 3111 is attached to the base layer 3119 with thebonding layer 3112 provided therebetween (see FIG. 23A). In theabove-described manner, the light-emitting device 3100 can bemanufactured (see FIG. 23B).

Next, steps for electrically connecting the terminal electrode 3116 andthe external electrode 3124 are described.

<Exposure of Surface of Terminal Electrode>

An adhesive tape is attached onto the portion 3121 a of the substrate3121, and then the adhesive tape is pulled upward to be removed, so thatthe portion 3121 a is separated from the substrate 3121 along the groove3141. At this time, the bonding layer 3120 and the layer 3105 that theportion 3121 a overlaps can be removed together with the portion 3121 abecause of low adhesion between the layer 3104 and the layer 3105 (seeFIG. 19A and FIG. 24A).

Note that the layer 3105 is not necessarily formed. However, the layer3105 is formed at the interface between the bonding layer 3120 and thelayer 3104, whereby the bonding layer 3120 that the portion 3121 aoverlaps hardly remains on the light-emitting device 3100 side at thetime of the separation of the portion 3121 a. Thus, by forming the layer3105 at the interface between the bonding layer 3120 and the layer 3104,manufacturing yield can be improved.

<Removal of Layer 3104>

Next, the layer 3104 is removed with an organic solvent such as ethylalcohol to expose part of a surface of the terminal electrode 3116 (seeFIG. 19B and FIG. 24B).

<Formation of External Electrode>

Next, the anisotropic conductive connection layer 3123 is formed in theopening 3122, and the external electrode 3124 for inputting electricpower or a signal to the light-emitting device 3100 is formed over theanisotropic conductive connection layer 3123 (see FIG. 24C). Theexternal electrode 3124 and the terminal electrode 3116 are electricallyconnected to each other through the anisotropic conductive connectionlayer 3123. Thus, electric power or a signal can be input to thelight-emitting device 3100. Note that the external electrode 3124 can beformed using a material and a method similar to those of the externalelectrode 124 disclosed in the above embodiment.

In one embodiment of the present invention, the groove 3141 is formed inthe substrate 3121, and the layer 3104 and the layer 3105 are formed atthe interface between the bonding layer 3120 and the terminal electrode3116, so that the terminal electrode 3116 can be exposed easily. Thus,there is no need to hollow out part of the substrate 3121 with a sharpedged tool or the like for exposure of the terminal electrode 3116;thus, the light-emitting device 3100 and the terminal electrode 3116 arenot easily damaged.

The layer 3104 can be formed in the same step as the EL layer 3117. Thelayer 3105 can be formed in the same step as the electrode 3118. Thus,the portion 3121 a can be removed easily without increasing the numberof manufacturing steps of the light-emitting device 3100. One embodimentof the present invention can provide a highly reliable light-emittingdevice having high manufacturing yield.

The portion 3121 a has a function of protecting the terminal electrode3116. The light-emitting device 3100 is stored and transferred withoutseparating the portion 3121 a, whereby the terminal electrode 3116 canbe protected when stored and transferred, and breakage of thelight-emitting device 3100 due to electrostatic electricity or the likecan be prevented.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 7

FIGS. 25A to 25E and FIGS. 26A to 26E are each an enlarged plan view ofa region of the substrate 3121 that overlaps the terminal electrode3116. FIGS. 25A to 25E and FIGS. 26A to 26E illustrate arrangementexamples of the grooves 3141.

In the plan view, a portion surrounded with the grooves 3141 is theportion 3121 a. In other words, the grooves 3141 are formed along theouter edge of the portion 3121 a. In the case where the grooves 3141penetrate the substrate 3121 in the thickness direction, it is necessaryto prevent a reduction in manufacturing yield due to unintentionalseparation of the portion 3121 a from the substrate 3121 beforeattachment of the substrate 3121 onto the substrate 3111. For thisreason, it is necessary to form at least two regions without grooves3141 along the outer edge of the portion 3121 a (the region ishereinafter called “gap a”).

FIGS. 25A to 25E and FIG. 26A each illustrate an example in which thegrooves 3141 are formed in the form of perforations along the outer edgeof the rectangular portion 3121 a in the plan view. Note that theperforations are continuously formed holes for facilitating separationand the groove 3141 corresponds to the hole.

In the case where the groove 3141 does not penetrate the substrate 3121in the thickness direction, unintentional separation of the portion 3121a can be prevented even if the grooves 3141 are not formed in the formof perforations. Thus, in the case where the groove 3141 does notpenetrate the substrate 3121 in the thickness direction, the outer edgeof the portion 3121 a can be surrounded with one groove 3141. Note thatthe grooves 3141 that do not penetrate the substrate 3121 in thethickness direction may be formed in the form of perforations.

In FIG. 25A, the groove 3141 is not formed in both ends of each shortside of the portion 3121 a, and the long side formed of the groove 3141and the short side formed of the groove 3141 are separated by the gap a.

FIG. 25B illustrates a modification example of the structure illustratedin FIG. 25A, in which the long sides of the portion 3121 a are eachformed of two grooves 3141.

Note that the length of the gap a is the shortest distance between anend of the groove 3141 and an end of the adjacent groove 3141. In thecase where a plurality of grooves 3141 are formed in the form ofperforations, a too large gap a makes the separation of the portion 3121a difficult. The length of the gap a is preferably 50 times or less,more preferably 20 times or less, still more preferably 10 times or lessof the thickness of the substrate 3121. In addition, the longer thelength b of one groove 3141 is, the easier the separation of the portion3121 a is. The length b of one groove 3141 is preferably longer than orequal to the length of the gap a.

FIG. 25C illustrates another modification example of the structureillustrated in FIG. 25A, in which each long side of the portion 3121 ais formed of eight grooves 3141.

FIG. 25D illustrates an example in which the grooves 3141 along theouter edge of the portion 3121 a that are separated in the middle of thefour sides of the portion 3121 a are provided. In FIG. 25D, the portion3121 a with a rectangular shape is made up of four L-shaped grooves3141.

FIG. 25E illustrates an example in which the grooves 3141 are formedalong the outer edge of the portion 3121 a and the gap a is provided inpart of each of the two short sides of the portion 3121 a. In FIG. 25E,the portion 3121 a is made up of two L-shaped grooves 3141.

FIG. 26A illustrates an example in which one long side and one shortside of the portion 3121 a are formed of the L-shaped groove 3141 andthe other long side and short side of the portion 3121 a are formed ofthe grooves 3141 in the form of perforations.

FIG. 26B illustrates an example in which the short sides of the portion3121 a are formed of dogleg grooves 3141.

FIG. 26C is a modification example in which the two parallel grooves3141 in FIG. 26B are formed of each a plurality of grooves 3141.

FIG. 26D is another modification example in which the dogleg grooves3141 in FIG. 26B are arc-shaped grooves 3141.

Ends of the portion 3121 a are extended outward in the plan view asillustrated in FIGS. 26B to 26D, whereby the portion 3121 a can beseparated more easily.

The grooves 3141 may be formed across the substrate 3121 as illustratedin FIG. 26E. However, ends of the portion 3121 a are easily in contactwith storage equipment, a jig, or the like at the time of storage ortransfer of the light-emitting device 3100, which might causeunintentional separation or partial separation of the portion 3121 a. Inaddition, when the portion 3121 a is separated to expose the terminalelectrode 3116, the mechanical strength of the region, i.e., theexternal electrode connection region is significantly decreased; thus,the external electrode connection region is easily deformedunintentionally, which easily causes breakage or the like of thelight-emitting device 3100.

Meanwhile, the portion 3121 a is formed inside edges of the substrate3121 in a plan view, so that the outer edge of the external electrodeconnection portion can be supported by the substrate 3111 and thesubstrate 3121. This can make it difficult to increase the mechanicalstrength of the external electrode connection region and can reduceunintentional deformation of the external electrode connection region.Thus, breakage of the light-emitting device 3100 can be prevented, andthe reliability of the light-emitting device 3100 can be improved.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 8

In this embodiment, a light-emitting device 3200 having a structuredifferent from the structure of the light-emitting device 3100 describedin the above embodiment is described with reference to FIGS. 27A and27B. FIG. 27A is a top view of the light-emitting device 3200, and FIG.27B is a cross-sectional view of a portion taken along the dashed-dottedline G1-G2 in FIG. 27A.

<Structure of Light-Emitting Device>

The light-emitting device 3200 described in this embodiment includes adisplay area 3231 and a peripheral circuit 3251. The light-emittingdevice 3200 also includes a terminal electrode 3216 and thelight-emitting element 3125 including the electrode 3115, the EL layer3117, and the electrode 3118. A plurality of light-emitting elements3125 are formed in the display area 3231. A transistor 3232 forcontrolling the amount of light emitted from the light-emitting element3125 is connected to each light-emitting element 3125.

The terminal electrode 3216 is electrically connected to the externalelectrode 3124 through the anisotropic conductive connection layer 3123formed in the opening 3122. In addition, the terminal electrode 3216 iselectrically connected to the peripheral circuit 3251.

The peripheral circuit 3251 includes a plurality of transistors 3252.The peripheral circuit 3251 has a function of determining which of thelight-emitting elements 3125 in the display area 3231 is supplied with asignal from the external electrode 3124.

In the light-emitting device 3200 illustrated in FIGS. 27A and 27B, thesubstrate 3111 and the substrate 3121 are attached to each other withthe bonding layer 3120 provided therebetween. An insulating layer 3205is formed over the substrate 3111 with the bonding layer 3112 providedtherebetween. The insulating layer 3205 can be formed using a materialand a method similar to those of the insulating layer 205 disclosed inthe above embodiment.

Note that the insulating layer 3205 functions as a base layer and canprevent or reduce diffusion of impurity elements from the substrate3111, the bonding layer 3112, or the like to the transistor or thelight-emitting element.

In addition, the transistor 3232, the transistor 3252, the terminalelectrode 3216, and a wiring 3219 are formed over the insulating layer3205. Note that although a channel-etched transistor that is a type ofbottom-gate transistor is illustrated as the transistor 3232 and thetransistor 3252 in this embodiment, a channel-protective transistor, atop-gate transistor, or the like can also be used. It is also possibleto use a dual-gate transistor, in which a semiconductor layer in which achannel is formed is interposed between two gate electrodes.

The transistor 3232 and the transistor 3252 may have the same structure.However, the size (e.g., channel length and channel width) or the likeof each transistor can be adjusted as appropriate.

The transistor 3232 and the transistor 3252 each include a gateelectrode 3206, a gate insulating layer 3207, a semiconductor layer3208, a source electrode 3209 a, and a drain electrode 3209 b.

The terminal electrode 3216, the wiring 3219, the gate electrode 3206,the source electrode 3209 a, and the drain electrode 3209 b can beformed using a material and a method similar to those of the terminalelectrode 3116. In addition, the gate insulating layer 3207 can beformed using a material and a method similar to those of the insulatinglayer 3205.

The semiconductor layer 3208 can be formed using a material and a methodsimilar to those of the semiconductor layer 208 disclosed in the aboveembodiment.

In the case where an oxide semiconductor is used for the semiconductorlayer 3208, an insulating layer containing oxygen is preferably used asan insulating layer that is in contact with the semiconductor layer3208.

In addition, an insulating layer 3210 is formed over the transistor 3232and the transistor 3252, and an insulating layer 3211 is formed over theinsulating layer 3210. The insulating layer 3210 functions as aprotective insulating layer and can prevent or reduce diffusion ofimpurity elements from a layer above the insulating layer 3210 to thetransistor 3232 and the transistor 3252. The insulating layer 3210 canbe formed using a material and a method similar to those of theinsulating layer 3205.

Planarization treatment may be performed on the insulating layer 3211 toreduce unevenness of a surface on which the light-emitting element 3125is formed. The planarization treatment may be, but not particularlylimited to, polishing treatment (e.g., chemical mechanical polishing) ordry etching treatment.

Forming the insulating layer 3211 using an insulating material with aplanarization function can omit polishing treatment. As the insulatingmaterial with a planarization function, for example, an organic materialsuch as a polyimide resin or an acrylic resin can be used. Other thanthe above-described organic materials, it is also possible to use alow-dielectric constant material (low-k material) or the like. Note thatthe insulating layer 3211 may be formed by stacking a plurality ofinsulating films formed of these materials.

In addition, over the insulating layer 3211, the light-emitting element3125 and the partition 3114 for separating the adjacent light-emittingelements 3125 are formed.

In addition, the substrate 3121 is provided with a light-shielding film3264, a coloring layer 3266, and an overcoat layer 3268. Thelight-emitting device 3200 is what is called a top-emissionlight-emitting device in which light emitted from the light-emittingelement 3125 is extracted from the substrate 3121 side through thecoloring layer 3266.

The light-emitting element 3125 is electrically connected to thetransistor 3232 through the opening formed in the insulating layer 3211and the insulating layer 3210.

Although an active matrix light-emitting device is described as anexample of the light-emitting device in this embodiment, the presentinvention can also be applied to a passive matrix light-emitting device.

One embodiment of the present invention can be applied to displaydevices such as a liquid crystal display device including a liquidcrystal element as a display element, an electronic paper, DMD, PDP,FED, and SED, without limitation to a light-emitting device including alight-emitting element as a display element.

An example of a liquid crystal element can be similar the liquid crystalelement disclosed in the above embodiment. A driving method of a liquidcrystal element can be similar to any of the driving methods of theliquid crystal element disclosed in the above embodiment.

A display method of an electronic paper can be similar to any of thedisplay methods of the electronic paper disclosed in the aboveembodiment.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 9

In this embodiment, structure examples of a light-emitting element thatcan be applied to the light-emitting element 125, the light-emittingelement 2125, and the light-emitting element 3125 are described. Notethat an EL layer 320 described in this embodiment corresponds to the ELlayer 117, the EL layer 2117, and the EL layer 3117 described in theabove embodiments.

<Structure of Light-Emitting Element>

In a light-emitting element 330 illustrated in FIG. 28A, the EL layer320 is interposed between a pair of electrodes (a first electrode 318and a second electrode 322). Note that the first electrode 318 is usedas an anode and the second electrode 322 is used as a cathode as anexample in the following description of this embodiment.

The EL layer 320 includes at least a light-emitting layer and may have astacked-layer structure including a functional layer other than thelight-emitting layer. As the functional layer other than thelight-emitting layer, a layer containing a substance having a highhole-injection property, a substance having a high hole-transportproperty, a substance having a high electron-transport property, asubstance having a high electron-injection property, a bipolar substance(a substance having high electron- and hole-transport properties), orthe like can be used. Specifically, functional layers such as ahole-injection layer, a hole-transport layer, an electron-transportlayer, and an electron-injection layer can be used in combination asappropriate.

The light-emitting element 330 illustrated in FIG. 28A emits light whencurrent flows because of a potential difference generated between thefirst electrode 318 and the second electrode 322 and holes and electronsare recombined in the EL layer 320. That is, the light-emitting regionis formed in the EL layer 320.

In the present invention, light emitted from the light-emitting element330 is extracted to the outside from the first electrode 318 side or thesecond electrode 322 side. Therefore, one of the first electrode 318 andthe second electrode 322 is formed of a light-transmitting substance.

Note that a plurality of EL layers 320 may be stacked between the firstelectrode 318 and the second electrode 322 as in a light-emittingelement 331 illustrated in FIG. 28B. In the case where n (n is a naturalnumber of 2 or more) layers are stacked, a charge generation layer 320 ais preferably provided between an m-th EL layer 320 and an (m+1)-th ELlayer 320. Note that m is a natural number greater than or equal to 1and less than n.

The charge generation layer 320 a can be formed using a compositematerial of an organic compound and a metal oxide, a metal oxide, acomposite material of an organic compound and an alkali metal, analkaline earth metal, or a compound thereof; alternatively, thesematerials can be combined as appropriate. Examples of the compositematerial of an organic compound and a metal oxide include compositematerials of an organic compound and a metal oxide such as vanadiumoxide, molybdenum oxide, and tungsten oxide. As the organic compound, avariety of compounds can be used; for example, low molecular compoundssuch as an aromatic amine compound, a carbazole derivative, and aromatichydrocarbon and high molecular compounds (e.g., oligomer, dendrimer, andpolymer). As the organic compound, it is preferable to use the organiccompound which has a hole-transport property and has a hole mobility of10⁻⁶ cm²/Vs or higher. However, substances other than the substancesgiven above may also be used as long as the substances have higherhole-transport properties than electron-transport properties. Thesematerials used for the charge generation layer 320 a have excellentcarrier-injection properties and carrier-transport properties; thus, thelight-emitting element 330 can be driven with low current and with lowvoltage.

Note that the charge generation layer 320 a may be formed with acombination of a composite material of an organic compound and a metaloxide and another material. For example, a layer containing a compositematerial of the organic compound and the metal oxide may be combinedwith a layer containing a compound of a substance selected fromsubstances with an electron-donating property and a compound with a highelectron-transport property. Moreover, a layer containing a compositematerial of the organic compound and the metal oxide may be combinedwith a transparent conductive film.

The light-emitting element 331 having such a structure is unlikely tohave problems such as energy transfer and quenching and has an expandedchoice of materials, and thus can easily have both high emissionefficiency and a long lifetime. Moreover, it is easy to obtainphosphorescence from one EL layer and fluorescence from the other ELlayer.

The charge generation layer 320 a has a function of injecting holes toone of the EL layers 320 that is in contact with the charge generationlayer 320 a and a function of injecting electrons to the other EL layer320 that is in contact with the charge generation layer 320 a, whenvoltage is applied to the first electrode 318 and the second electrode322.

The light-emitting element 331 illustrated in FIG. 28B can provide avariety of emission colors by changing the type of the light-emittingsubstance used for the EL layer 320. In addition, a plurality oflight-emitting substances emitting light of different colors may be usedas the light-emitting substances, whereby light emission having a broadspectrum or white light emission can be obtained.

In the case of obtaining white light emission using the light-emittingelement 331 illustrated in FIG. 28B, as for the combination of aplurality of EL layers, a structure for emitting white light includingred light, green light, and blue light may be used; for example, thestructure may include a first light-emitting layer containing a bluefluorescent substance as a light-emitting substance and a secondlight-emitting layer containing red and green phosphorescent substancesas light-emitting substances. Alternatively, a structure including afirst light-emitting layer emitting red light, a second light-emittinglayer emitting green light, and a third light-emitting layer emittingblue light may be employed. Further alternatively, with a structureincluding light-emitting layers emitting light of complementary colors,white light emission can be obtained. When light emitted from the firstlight-emitting layer and light emitted from the second light-emittinglayer have complementary colors to each other in a stacked-layer elementincluding two light-emitting layers, the combinations of colors are asfollows: blue and yellow, blue-green and red, and the like.

Note that in the structure of the above-described stacked-layer element,by providing the charge generation layer between the stackedlight-emitting layers, the element can have a long lifetime in ahigh-luminance region while keeping the current density low. Inaddition, the voltage drop due to the resistance of the electrodematerial can be reduced, whereby uniform light emission in a large areais possible.

This embodiment can be implemented in an appropriate combination withany of the structures described in the other embodiments.

Embodiment 10

In this embodiment, examples of an electronic appliance and a lightingdevice including the light-emitting device of one embodiment of thepresent invention are described with reference to drawings.

As examples of electronic appliances with flexibility, the following canbe given: television devices (also called televisions or televisionreceivers), monitors of computers or the like, digital cameras, digitalvideo cameras, digital photo frames, mobile phones (also called cellularphones or mobile phone devices), portable game machines, portableinformation terminals, audio reproducing devices, large game machinessuch as pachinko machines, and the like.

In addition, a lighting device or a display device can be incorporatedalong a curved inside/outside wall surface of a house or a building or acurved interior/exterior surface of a car.

FIG. 29A illustrates an example of a mobile phone. A mobile phone 7400is provided with a display portion 7402 incorporated in a housing 7401,an operation button 7403, an external connection port 7404, a speaker7405, a microphone 7406, and the like. Note that the mobile phone 7400is manufactured using the light-emitting device in the display portion7402.

When the display portion 7402 of the mobile phone 7400 illustrated inFIG. 29A is touched with a finger or the like, data can be input to themobile phone 7400. Further, operations such as making a call andinputting a character can be performed by touch on the display portion7402 with a finger or the like.

The power can be turned on or off with the operation button 7403. Inaddition, types of images displayed on the display portion 7402 can beswitched; for example, switching images from a mail creation screen to amain menu screen.

Here, the display portion 7402 includes the light-emitting device of oneembodiment of the present invention. Thus, the mobile phone can have acurved display portion and high reliability.

FIG. 29B is an example of a wristband-type display device. A portabledisplay device 7100 includes a housing 7101, a display portion 7102, anoperation button 7103, and a sending and receiving device 7104.

The portable display device 7100 can receive a video signal with thesending and receiving device 7104 and can display the received video onthe display portion 7102. In addition, with the sending and receivingdevice 7104, the portable display device 7100 can send an audio signalto another receiving device.

With the operation button 7103, power ON/OFF, switching displayedvideos, adjusting volume, and the like can be performed.

Here, the display portion 7102 includes the light-emitting device of oneembodiment of the present invention. Thus, the portable display devicecan have a curved display portion and high reliability.

FIGS. 29C to 29E illustrate examples of lighting devices. A lightingdevice 7200, a light-emitting device 7210, and a light-emitting device7220 each include a stage 7201 provided with an operation switch 7203and a light-emitting portion supported by the stage 7201.

The lighting device 7200 illustrated in FIG. 29C includes alight-emitting portion 7202 with a wave-shaped light-emitting surfaceand thus is a good-design lighting device.

A light-emitting portion 7212 included in the lighting device 7210illustrated in FIG. 29D has two convex-curved light-emitting portionssymmetrically placed. Thus, light radiates from the lighting device7210.

The lighting device 7220 illustrated in FIG. 29E includes aconcave-curved light-emitting portion 7222. This is suitable forilluminating a specific range because light emitted from thelight-emitting portion 7222 is collected to the front of the lightingdevice 7220.

The light-emitting portion included in each of the lighting devices7200, 7210, and 7220 are flexible; thus, the light-emitting portion maybe fixed on a plastic member, a movable frame, or the like so that anemission surface of the light-emitting portion can be bent freelydepending on the intended use.

The light-emitting portions included in the lighting devices 7200, 7210,and 7220 each include the light-emitting device of one embodiment of thepresent invention. Thus, the lighting devices can have curvedlight-emitting portions and high reliability.

FIG. 30A illustrates an example of a portable display device. A displaydevice 7300 includes a housing 7301, a display portion 7302, operationbuttons 7303, a display portion pull 7304, and a control portion 7305.

The display device 7300 includes a rolled flexible display portion 7102in the cylindrical housing 7301.

The display device 7300 can receive a video signal with the controlportion 7305 and can display the received video on the display portion7302. In addition, a battery is included in the control portion 7305.Moreover, a connector may be included in the control portion 7305 sothat a video signal or power can be supplied directly.

With the operation buttons 7303, power ON/OFF, switching of displayedvideos, and the like can be performed.

FIG. 30B illustrates a state in which the display portion 7302 is pulledout with the display portion pull 7304. Videos can be displayed on thedisplay portion 7302 in this state. Further, the operation buttons 7303on the surface of the housing 7301 allow one-handed operation.

Note that a reinforcement frame may be provided for an edge portion ofthe display portion 7302 in order to prevent the display portion 7302from being curved when pulled out.

Note that in addition to this structure, a speaker may be provided forthe housing so that sound is output with an audio signal receivedtogether with a video signal.

The display portion 7302 includes the light-emitting device of oneembodiment of the present invention. Thus, the display portion 7302 is aflexible, highly reliable display portion, which makes the displaydevice 7300 lightweight and highly reliable.

It is needless to say that one embodiment of the present invention isnot limited to the above-described electronic appliances and lightingdevices as long as the light-emitting device of one embodiment of thepresent invention is included.

This embodiment can be combined with any of the other embodimentsdisclosed in this specification as appropriate.

This application is based on Japanese Patent Application serial no.2013-051231 filed with the Japan Patent Office on Mar. 14, 2013,Japanese Patent Application serial no. 2013-093328 filed with the JapanPatent Office on Apr. 26, 2013, and Japanese Patent Application serialno. 2013-120369 filed with the Japan Patent Office on Jun. 7, 2013, theentire contents of which are hereby incorporated by reference.

What is claimed is:
 1. A method for manufacturing a light-emittingdevice, comprising the steps of: forming a terminal electrode and alight-emitting element comprising an EL layer over a substrate, whereina first layer comprising an organic compound contained in the EL layeris provided over the terminal electrode; forming a first substratehaving a first opening over the light-emitting element and the terminalelectrode with a bonding layer having a second opening interposedtherebetween, wherein the terminal electrode, the first layer, the firstopening, and the second opening are overlapped with each other; exposinga part of the terminal electrode by removing the first layer with anorganic solvent; forming an anisotropic conductive connection layer inthe first opening and the second opening; and forming an externalelectrode electrically connected to the terminal electrode through theanisotropic conductive connection layer.
 2. The method for manufacturinga light-emitting device, according to claim 1, wherein the firstsubstrate is a flexible substrate.
 3. The method for manufacturing alight-emitting device, according to claim 1, wherein the organic solventis an ethyl alcohol.
 4. The method for manufacturing a light-emittingdevice, according to claim 1, wherein the EL layer comprises alight-emitting layer.
 5. The method for manufacturing a light-emittingdevice, according to claim 1, wherein the organic compound is alight-emitting substance.
 6. The method for manufacturing alight-emitting device, according to claim 1, wherein the terminalelectrode comprises a three-layer metal film in which aluminum isinterposed between two layers of molybdenum.
 7. A method formanufacturing a light-emitting device, comprising the steps of: forminga separation layer over a substrate; forming a base layer over theseparation layer; forming a terminal electrode and a light-emittingelement comprising an EL layer over the base layer, wherein a firstlayer comprising an organic compound contained in the EL layer isprovided over the terminal electrode; forming a first substrate having afirst opening over the light-emitting element and the terminal electrodewith a bonding layer having a second opening interposed therebetween,wherein the terminal electrode, the first layer, the first opening, andthe second opening are overlapped with each other; exposing a part ofthe terminal electrode by removing the first layer with an organicsolvent; forming an anisotropic conductive connection layer in the firstopening and the second opening; and forming an external electrodeelectrically connected to the terminal electrode through the anisotropicconductive connection layer.
 8. The method for manufacturing alight-emitting device, according to claim 7, wherein the first substrateis a flexible substrate.
 9. The method for manufacturing alight-emitting device, according to claim 7, wherein the organic solventis an ethyl alcohol.
 10. The method for manufacturing a light-emittingdevice, according to claim 7, wherein the EL layer comprises alight-emitting layer.
 11. The method for manufacturing a light-emittingdevice, according to claim 7, wherein the organic compound is alight-emitting substance.
 12. The method for manufacturing alight-emitting device, according to claim 7, wherein the terminalelectrode comprises a three-layer metal film in which aluminum isinterposed between two layers of molybdenum.
 13. The method formanufacturing a light-emitting device, according to claim 7, wherein theseparation layer comprises tungsten.
 14. The method for manufacturing alight-emitting device, according to claim 7, wherein the base layer isformed of silicon oxide.
 15. A method for manufacturing a light-emittingdevice, comprising the steps of: forming a separation layer over asubstrate; forming a base layer over the separation layer; forming aterminal electrode over the base layer; forming a first electrodeelectrically connected to the terminal electrode; forming an EL layercomprising an organic compound over the first electrode; forming a firstlayer comprising the organic compound overlapping the terminalelectrode, the EL layer and the first layer being formed simultaneously;forming a second electrode comprising a metal element over the EL layer;forming a first substrate having a first opening over the secondelectrode and the terminal electrode with a bonding layer having asecond opening interposed therebetween, wherein the terminal electrode,the first layer, the first opening, and the second opening areoverlapped with each other; exposing a part of the terminal electrode byremoving the first layer with an organic solvent; forming an anisotropicconductive connection layer in the first opening and the second opening;and forming an external electrode electrically connected to the terminalelectrode through the anisotropic conductive connection layer.
 16. Themethod for manufacturing a light-emitting device, according to claim 15,wherein the first substrate is a flexible substrate.
 17. The method formanufacturing a light-emitting device, according to claim 15, whereinthe organic solvent is an ethyl alcohol.
 18. The method formanufacturing a light-emitting device, according to claim 15, whereinthe EL layer comprises a light-emitting layer.
 19. The method formanufacturing a light-emitting device, according to claim 15, whereinthe organic compound is a light-emitting substance.
 20. The method formanufacturing a light-emitting device, according to claim 15, whereinthe terminal electrode comprises a three-layer metal film in whichaluminum is interposed between two layers of molybdenum.
 21. The methodfor manufacturing a light-emitting device, according to claim 15,wherein the separation layer comprises tungsten.
 22. The method formanufacturing a light-emitting device, according to claim 15, whereinthe base layer is formed of silicon oxide.